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Asked/Added Questions From NCERT:

Question 1. Asked on :12 September 2020:05:53:51 PM

Account for Bond dissociation energy of F2 is less than that of Cl2.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Due to smaller size of F than Cl as a result of which electron-electron repulsions between the lone pairs of electrons are very large than that of Cl, hence bond dissociation energy of F2 is less than that of Cl2.

-Answered by Shruti Srivastva On 12 September 2020:05:55:10 PM


Question 2. Asked on :12 September 2020:05:51:14 PM

Explain the role of Cryolite in the electrolytic reduction of alumina. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Lower the melting point of the mixture and brings conductivity. 

-Answered by Shruti Srivastva On 12 September 2020:05:52:37 PM


Question 3. Asked on :12 September 2020:05:50:10 PM

Give ann example of elastomers. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Buna-S, Buna-N.

-Answered by Shruti Srivastva On 12 September 2020:05:50:54 PM


Question 4. Asked on :12 September 2020:05:49:24 PM

What is an alkylamine more basic than ammonia? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Rohit Rajput
 This is because of electron releasing tendency of alkyl group. The alkyl group shows +I effect which increases the electron density at N atom in alkyl amine which makes it more basic than ammonia.

-Answered by Rohit Rajput On 26 September 2020:07:19:07 PM


Question 5. Asked on :12 September 2020:05:45:37 PM

What is Bi a stronger oxidant than Sb? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
The stability of the +5 oxidant state decreases and that of +3 state increases due to the inert pair effect down the group therefore Bi accepts two electrons and get reduced to Bi. 

-Answered by Shruti Srivastva On 12 September 2020:05:46:50 PM


Question 6. Asked on :12 September 2020:05:42:17 PM

Why is the forth flotation method selected for the concentration of sulphide ores? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Because the method is based on preferential wetting properties with the frothing agent and water, and the suphide particles of res stick to the oil droplets and rise in the form of forth. 

-Answered by Shruti Srivastva On 12 September 2020:05:43:21 PM


Question 7. Asked on :12 September 2020:05:41:18 PM

Define the term "Tyndall effect".

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

nisha sheikh
Tyndall effect, also called Tyndall phenomenon, scattering of a beam of light by a medium containing small suspended particles—e.g., smoke or dust in a room, which makes visible a light beam entering a window.

-Answered by nisha sheikh On 20 September 2020:06:57:34 PM


Question 8. Asked on :12 September 2020:05:39:05 PM

Which point defect in crystals doesn't alter the density of the relevant solid? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Frenkel defect. 

-Answered by Shruti Srivastva On 12 September 2020:05:40:59 PM


Question 9. Asked on :11 September 2020:05:43:44 PM

You are staying near a fertilizer factory. In the middle of the might there is a leakage of ammonia which is detected by the smell . Within 10 minutes you ind the smell is introleable. 

What value is derieved from this? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Alertness. 

-Answered by Shruti Srivastva On 11 September 2020:05:46:36 PM


Question 10. Asked on :11 September 2020:05:38:10 PM

 What first aid measures will you take againd=st the gas pill acciedent for yourself and your neighbours?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Keeping a wet hankerchief in our mouth. 

-Answered by Shruti Srivastva On 11 September 2020:05:43:06 PM


Question 11. Asked on :11 September 2020:05:34:17 PM

In 2007, Matttel company, the makers o barbie doll recalled nearly one million toys in USA.

By this act of company what values are reflected in the above case? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Safety of small childrens. 

-Answered by Shruti Srivastva On 11 September 2020:05:37:46 PM


Question 12. Asked on :11 September 2020:05:32:24 PM

Can you suggest the reason for recall of toys? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Small children generally put the toys in their mouth while playing with them . 

-Answered by Shruti Srivastva On 11 September 2020:05:33:28 PM


Question 13. Asked on :11 September 2020:05:30:24 PM

Name the metal which is present in paint used in automobile battries? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Lead (pb). 

-Answered by Shruti Srivastva On 11 September 2020:05:32:02 PM


Question 14. Asked on :11 September 2020:05:29:07 PM

Write the values which are ignored by the lab assisteant.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Safety and security.

-Answered by Shruti Srivastva On 11 September 2020:05:30:04 PM


Question 15. Asked on :11 September 2020:05:23:34 PM

A lab assistant wanted to dilute conc. H2SO4. He added water to conc. H2SO4. It started burning and librated a large amount o heat.

What mistakes was the lab assistant making? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
He doesn't know that water should not be added to conc. 

-Answered by Shruti Srivastva On 11 September 2020:05:27:52 PM


Question 16. Asked on :10 September 2020:11:17:54 AM

Define osmotic pressure. How is osmotic pressure related to the concentration of a solute in a solution?

-Added by Rohit Rajput Chemistry » Chemistry

Answer:

Rohit Rajput
Osmotic pressure is the measure of excess presure applied on solution side to stop the process od osmotic. Osmotic pressure is directly proportional to the concentration off solute in the solution.

  

-Answered by Rohit Rajput On 10 September 2020:11:23:48 AM


Question 17. Asked on :10 September 2020:11:16:28 AM

Explain the following terms with suitable examples?

(i) Frenkel defect (ii) F-centres.

-Added by Rohit Rajput Chemistry » Chemistry

Answer:

Rohit Rajput
(i) Frenkel defect- The defect in which the smaller ion/cation is dislocated to a nearby interstitial site.

Ex- Silver halides, ZnS.

(ii) F-centres- The aninon vacancy occupied by an electrons is called F-centres in Alkali metal halides.

Ex- NaCL, KCL, LiCL.

-Answered by Rohit Rajput On 10 September 2020:11:26:17 AM


Question 18. Asked on :10 September 2020:11:02:33 AM

What are Associated Colloids? Given an example?

-Added by Rohit Rajput Chemistry » Chemistry

Answer:

Rohit Rajput
Colloids which acts as electrolyte at low concentration and show colloidal behaviour at high concentration are called Associated colloids.

Ex- Soap solution and detergents.

-Answered by Rohit Rajput On 10 September 2020:11:09:12 AM


Question 19. Asked on :10 September 2020:11:01:09 AM

Why is tyndall effect shown by colloidal solutions? 

-Added by Rohit Rajput Chemistry » Chemistry

Answer:

Rohit Rajput
It is true to large size of colloidal particles. In colloidal solution particle size of dispersed phase is comparable to the wavelength of light used.


-Answered by Rohit Rajput On 10 September 2020:11:11:57 AM


Question 20. Asked on :10 September 2020:10:57:35 AM

Define the rate constant (k).

-Added by Rohit Rajput Chemistry » Chemistry

Answer:

Rohit Rajput
Rate constant: It is defined as the rate of reaction when the concentration of reactants is taken as unity.

-Answered by Rohit Rajput On 10 September 2020:11:15:09 AM


Question 21. Asked on :28 August 2020:05:25:25 PM

A soap manufacturer is marketing a soap claiming that the soap can be used for washing clothes in any kind of Water. Later, it is formed that the soap does not work with the groundwater.

List the values that are not considered by the company. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
(i) Fair dealing

(ii) Business ethics.

(iii) Selling a non-standardized products with the help of false advertisements. 

-Answered by Shruti Srivastva On 28 August 2020:05:30:26 PM


Question 22. Asked on :28 August 2020:05:22:09 PM

A soap manufacturer is marketing a soap claiming that the soap can be used for washing clothes in any kind of Water. Later, it is formed that the soap does not work with the groundwater.

What went wrong with it?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Groundwater is hard water and it contains Ca+2 and Mg+2 salts which react with soap produce a curdy precipitate that adheres to the fabric as gummy mass and blocks the ability of soap to remove dirt.

-Answered by Shruti Srivastva On 28 August 2020:05:27:30 PM


Question 23. Asked on :28 August 2020:05:19:33 PM

As a citizen of the country what should be our course of action further during coal mine?  

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
We have to inform the concerned authority about the excess of CO in the coal mine. 

-Answered by Shruti Srivastva On 28 August 2020:05:21:19 PM


Question 24. Asked on :28 August 2020:05:17:41 PM

How could we estimate the level of pollutants during a coal mine?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
By using I2O5.

-Answered by Shruti Srivastva On 28 August 2020:05:19:09 PM


Question 25. Asked on :27 August 2020:06:01:58 PM

Why it is difficulty in breathing in a coal m

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
In coal mines to lack of oxygen, a small percentage of carbon monoxide is formed. 

-Answered by Shruti Srivastva On 27 August 2020:06:03:37 PM


Question 26. Asked on :27 August 2020:05:51:35 PM

Write the feature of the cadmium plate battery?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva

Cadmium plate battery through expensive is not as strong a pollutant as a lead. Lead salt beings insoluble in water if ingested into our system cannot be excreted out. Whereas Cd and Ni salts are water-soluble. therefor get biomagnified in the body. 

-Answered by Shruti Srivastva On 27 August 2020:05:52:27 PM


Question 27. Asked on :27 August 2020:05:45:06 PM

What kind of organizational values are ignored that could affect the people living in the area?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
The industry is ignoring its social responsibility for the health and safety of people and respect for the environment. Due to water and air pollution caused by the industry, the entire ecological system will collapse. 

-Answered by Shruti Srivastva On 27 August 2020:05:46:25 PM


Question 28. Asked on :27 August 2020:05:43:27 PM

Copper pyrite is the copper-ore used in the unit. The harmful gases emmited are CO, SO2, SO3, etc. 

-Added by Shruti Srivastva Chemistry » Chemistry


Question 29. Asked on :25 August 2020:05:34:31 PM

Write any three values which were ignored by the engineer and the workers. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
(i) Lack of safety and security.

(ii) Lack of value for human life. 

(iii) Lack of responsibility towards their own amilies and society at large. 

-Answered by Shruti Srivastva On 25 August 2020:05:35:37 PM


Question 30. Asked on :25 August 2020:05:29:14 PM

Why are gas masks used in deep coal mining?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva

Gas masks containing activated charcoal are frequently used by miners. Poisonous gases like CH4, CO etc. can be selectively absorbed by the gas masks containing activated charcoal. 

-Answered by Shruti Srivastva On 25 August 2020:05:32:39 PM


Question 31. Asked on :24 August 2020:05:53:48 PM

What could be the reason for Electric use?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Anjali Kumari
Causes of high electricity usage
5 Reasons Your Electric Bill is So High
  • Letting Vampire Appliances Bleed You Dry. One of the main reasons your electric bill may be high is that you leave your appliances or electronics plugged in whether you're using them or not. ...
  • Feeding Energy Hog Appliances. ...
  • Misusing Lights and Ceiling Fans. ...
  • Using Appliances Past Their Prime. ...
  • Device-Charging Frenzy.

-Answered by Anjali Kumari On 12 October 2020:07:24:21 PM


Question 32. Asked on :24 August 2020:05:49:16 PM

Why are the gas masks used in deep coal-mining?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Gas mask containing activated charcoal are frequently used by miners. Poisonous gases like CH4, CO, etc. can be selectively absorbed by the gas mask containing activated charcoal. 

-Answered by Shruti Srivastva On 24 August 2020:05:51:22 PM


Question 33. Asked on :24 August 2020:05:47:54 PM

Name any two macro molecules chosen as drug targets. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Lipid and Protiens.

-Answered by Shruti Srivastva On 24 August 2020:05:48:57 PM


Question 34. Asked on :24 August 2020:05:45:07 PM

Give an example of a substance that can act as a disinfect as well as antiseptic depending upon its concentration. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva

 0.2% solution of phenol acts as antiseptic whereas 1 % solution o phenol acts as disinfectant. 

-Answered by Shruti Srivastva On 24 August 2020:05:46:50 PM


Question 35. Asked on :24 August 2020:05:40:55 PM

Pick out the odd one from among the following on the basis o their medicinal properties mentioning the reason: Luminal, Seconal, Phenacetin, Equanil.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Phenacetin is an antipyretic, while the rest are tranquilizers. 

-Answered by Shruti Srivastva On 24 August 2020:05:43:40 PM


Question 36. Asked on :24 August 2020:04:49:07 PM

Describe the type of hybridisation for the complex ion [Fe(H2O)6]2+.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Fe exists as Fe2+.There are 4 unpaired electrons. Water is weak ligand. Thus the hybridisation involved is sp3d2. It is an octahedral outer d-orbital complex. 

-Answered by Shruti Srivastva On 24 August 2020:04:56:36 PM


Question 37. Asked on :24 August 2020:04:46:40 PM

What form Freundlich absorption equation will take at high pressure?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva

At high pressure, amount of gas absorbed (x/m) becomes independent of pressure (P). 

-Answered by Shruti Srivastva On 24 August 2020:04:47:48 PM


Question 38. Asked on :24 August 2020:04:44:33 PM

Why are lyophilic colloidal sols more stable than lyphobic colloidal sols?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
(i) Same charge on all the colloidal particles.

(ii) Solvation of the colloidal particle. 

-Answered by Shruti Srivastva On 24 August 2020:04:45:39 PM


Question 39. Asked on :24 August 2020:04:41:17 PM

What happens when a freshly precipated Fe(OH)3 is shaken with a little amount of dilute solution of FeCl3?

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
A reddish brown coloured solution is obtained. 

-Answered by Shruti Srivastva On 24 August 2020:04:43:43 PM


Question 40. Asked on :24 August 2020:04:38:50 PM

Predict the major product of acid catalysed dehydration of 1-Methylcyclohexanol.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva

1-Methylcyclohexene

-Answered by Shruti Srivastva On 24 August 2020:04:40:51 PM


Question 41. Asked on :24 August 2020:04:35:05 PM

Arrange them in order: 

PH2, AsH3, BiH3,SbH3, NH3 - Increasing base strength

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
 BiH3,< SbH3 < AsH3< PH2< NH3

-Answered by Shruti Srivastva On 24 August 2020:04:37:26 PM


Question 42. Asked on :24 August 2020:04:29:40 PM

Arrange them in order:

F2, Cl2, Br2, I2 - increasing bond dissociation enthalpy. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
L2<F2<Br2<Cl2

-Answered by Shruti Srivastva On 24 August 2020:04:32:09 PM


Question 43. Asked on :24 August 2020:04:28:31 PM

Ore used in the preparation of potassium dichromate. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Chromite ore. 

-Answered by Shruti Srivastva On 24 August 2020:04:29:27 PM


Question 44. Asked on :24 August 2020:04:26:52 PM

A member of the lanthanoid series which is well known to exhibit +4 oxidation state. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Cerium (Ce). 

-Answered by Shruti Srivastva On 24 August 2020:04:28:10 PM


Question 45. Asked on :24 August 2020:04:25:37 PM

A compound where the transition metal in the +7 oxidation state. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
KMnO4.

-Answered by Shruti Srivastva On 24 August 2020:04:26:31 PM


Question 46. Asked on :24 August 2020:04:19:02 PM

A transition metal which does not exhibit variation in oxidation state in its compound. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Scandium (Sc)

-Answered by Shruti Srivastva On 24 August 2020:04:21:00 PM


Question 47. Asked on :24 August 2020:04:16:06 PM

Give the IUPAC name and structure of the amine obtained when 3-chlorobutatnamide undergoes Hoffmann-bromamide reaction.

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Three ions [Co(NH3)6]2+,2Cl-

-Answered by Shruti Srivastva On 24 August 2020:04:17:42 PM


Question 48. Asked on :24 August 2020:04:12:45 PM

Amongst the isomeric alkanes of molecular formula C5H12, Identity that one on that on photochemical chloronitation yields a single monochloride.  

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Neopentate or 2, 2-Dimethylpropane. 

-Answered by Shruti Srivastva On 24 August 2020:04:15:27 PM


Question 49. Asked on :24 August 2020:04:10:44 PM

What is shape selectively catalysis? 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Catalysis by zeolites which depends on the shape and size of the reactants and the products as compared to those of the pores and cavities of zeolites. 

-Answered by Shruti Srivastva On 24 August 2020:04:11:23 PM


Question 50. Asked on :24 August 2020:04:07:16 PM

Name the non stoichiometric point defect responsible for colour in alkali metal halides. 

-Added by Shruti Srivastva Chemistry » Chemistry

Answer:

Shruti Srivastva
Metal excess or anionic vacancies or F-centres. 

-Answered by Shruti Srivastva On 24 August 2020:04:10:02 PM


Question 51. Asked on :03 February 2020:06:43:20 PM

Why respiration considered as Exothermic reaction?

-Added by Akki chauhan Science » Chemistry


Question 52. Asked on :03 February 2020:06:42:38 PM

Why we store silver chloride in dark bottles?

-Added by Akki chauhan Science » Chemistry

Answer:

priyanshu kumar
Silver chloride is stored in dark coloured bottles because it reacts with sunlight and decomposes to form silver and chlorine gas. So to prevent this it is stored in dark coloured bottles. the type of reaction is photolytic decomposition reaction.

-Answered by priyanshu kumar On 17 February 2020:02:51:34 PM


Question 53. Asked on :03 February 2020:06:41:54 PM

Write chemical equation of decomposition reaction?

-Added by Akki chauhan Science » Chemistry

Answer:

priyanshu kumar
A decomposition reaction occurs when one reactant breaks down into two or more products. This can be represented by the general equation: AB → A + B. Examples of decomposition reactions include the breakdown of hydrogen peroxide to water and oxygen, and the breakdown of water to hydrogen and oxygen

-Answered by priyanshu kumar On 17 February 2020:02:51:43 PM


Question 54. Asked on :03 February 2020:06:41:04 PM

What happens when quick lime is added to water?

-Added by Akki chauhan Science » Chemistry

Answer:

priyanshu kumar
When Calcium oxide i.e. quick lime is added to water filled in a bucket, it reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of he

-Answered by priyanshu kumar On 17 February 2020:02:51:53 PM


Question 55. Asked on :13 September 2019:07:09:35 PM

Pappu Karki, the popular Kumaoni folk singer has passed away. He was native of which state?

-Added by Akki chauhan Chemistry » Chemistry

Answer:

priyanshu kumar

 Uttarakhand


-Answered by priyanshu kumar On 03 October 2019:12:34:18 PM


Question 56. Asked on :13 September 2019:07:03:15 PM

Write is not a chemical change ?

-Added by Akki chauhan Chemistry » Chemistry

Answer:

priyanshu kumar
Crystallization of table salt from sea water

-Answered by priyanshu kumar On 03 October 2019:12:34:52 PM


Question 57. Asked on :13 September 2019:07:02:51 PM

 Which one of the following non metals is not a poor conductor of electricity

-Added by Akki chauhan Chemistry » Chemistry

Answer:

priyanshu kumar

 Selenium.


-Answered by priyanshu kumar On 03 October 2019:12:35:01 PM


Question 58. Asked on :02 July 2019:07:37:57 PM

Write the chemical formula of the following products:

(a) Sugar               (b) Glucose             (c) Vinegar            (d) Pyruvic acid 

(e) Tartaric Acid           

-Added by Himanshi Verma Science » Chemistry

Answer:

Akki chauhan

 (a) sugar C12H22O11

 (b) Glucose C6H12O6

 (c) Vinegar CH3COOH

 (d) Pyruvic C3H4O3

 (e) Tartaric C4H6O6

-Answered by Akki chauhan On 05 July 2019:09:13:27 AM


Question 59. Asked on :02 July 2019:04:47:31 PM

Why the cooking utensils are made up of aluminum brass and steel?

-Added by Himanshi Verma Science » Chemistry

Answer:

Akki chauhan

 Cooking utensils are made up of metal because utensils need to conduct heat well, but also need to chemically unreactive so that they do not alter the flavor of the food . most material that conductive enough to heat evenly are to use in food preparation.

-Answered by Akki chauhan On 05 July 2019:09:05:00 AM


Question 60. Asked on :22 March 2019:04:32:24 PM

 Why it is dangerous to sleep in an unventilated room with fair burning

-Added by Gunnaj sheikh Science » Chemistry

Answer:

Himanshi Verma

 It is dangerous to sleep in an inventilated room with fire burning inside because the fire produce carbon monoxide and carbon dioxide gases which are very harmful for us.

-Answered by Himanshi Verma On 22 March 2019:04:37:33 PM


Question 61. Asked on :11 February 2019:09:34:51 AM

 what do you mean by borax ?

-Added by Himanshi Verma Science » Chemistry

Answer:

Himanshi Verma

 Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. Powdered borax is white, consisting of soft colorless crystals that dissolve easily in water. Borax has a wide variety of uses.

-Answered by Himanshi Verma On 11 February 2019:05:42:09 PM


Question 62. Asked on :11 February 2019:09:30:54 AM

 why do we need to classify elements ?

-Added by Himanshi Verma Science » Chemistry

Answer:

Himanshi Verma

 The number of elements discovered has increased, making it difficult to remember the behavior and properties of these elements. Hence it is important to classify elements according to their properties. ... It helps us understand how different elements form different compounds.

-Answered by Himanshi Verma On 11 February 2019:05:42:36 PM


Question 63. Asked on :27 January 2019:11:20:09 AM

 find the very reactive  metals? 

-Added by SURAJ KUMAR Science » Chemistry

Answer:

Himanshi Verma

 Francium is the high reactive metal.

-Answered by Himanshi Verma On 02 February 2019:01:42:40 PM


Question 64. Asked on :27 January 2019:11:11:38 AM

 find the atomic number and valancy of potasium

-Added by kunal kumar Science » Chemistry

Answer:

Himanshi Verma

 Atomic number is 19 and valency is 1

-Answered by Himanshi Verma On 02 February 2019:01:44:01 PM


Question 65. Asked on :27 January 2019:11:02:35 AM

 write the formula of bleching power.

-Added by SURAJ KUMAR Science » Chemistry

Answer:

Nitish kumar

 Ca(ClO)2

-Answered by Nitish kumar On 27 January 2019:03:13:16 PM


Question 66. Asked on :27 January 2019:10:27:57 AM

 write the equation of endothermic and exothermic reaction ?

-Added by praful kumar Science » Chemistry

Answer:

Himanshi Verma

 Endothermic reaction examples equations

Endothermic vs. exothermic reactions
  • The teacher replies: “That's because you were given two different salts. ...
  • Consider the reaction mixture—salt plus water—as the system and the flask as the surrounding.
  • 1) Photosynthesis: Plants absorb heat energy from sunlight to convert carbon dioxide and water into glucose and oxygen.

-Answered by Himanshi Verma On 02 February 2019:01:48:05 PM


Question 67. Asked on :16 January 2019:06:16:06 PM

 Which of the following subtances undergo sublimation on heating 

a) Iodine     b) Napthelene             c) Camphor 

-Added by Himanshi Verma Science » Chemistry

Answer:

Master Purushottam
 The subtances which undergo sublimation on heating is napthelene and camphor.

-Answered by Master Purushottam On 24 August 2019:12:14:51 AM


Question 68. Asked on :14 January 2019:09:16:13 AM

 Write the chemical formula of Sodium bicarbonate

-Added by Akki chauhan Science » Chemistry

Answer:

Master Purushottam
  NaHCO3

-Answered by Master Purushottam On 23 August 2019:11:48:39 PM


 

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