Outline the principles behind the refining of metals by the foll

Subject

Chemistry

Class

CBSE Class 12

Pre Boards

Practice to excel and get familiar with the paper pattern and the type of questions. Check you answers with answer keys provided.

Sample Papers

Download the PDF Sample Papers Free for off line practice and view the Solutions online.
Advertisement

 Multiple Choice QuestionsShort Answer Type

1.

Give one example each of 'oil in water' and 'water in oil' emulsion.

3239 Views

2.

Which reducing agent is employed to get copper from the leached low-grade copper ore?

1910 Views

3.

Which of the following is a more stable complex and why?

 (i) [Co(NH3)6]3+

 (ii) [Co(en)3]3+

4251 Views

4.

An element with density 11.2 g cm-3  forms a f.c.c. lattice with edge length of 4 x10-8

Calculate the atomic mass of the element. (Given:  NA = 6.022x 10-23 (mol-1

2537 Views

Advertisement
5.

Examine the given defective crystal:
 

Answer the following questions:


(i) What type of stoichiometric defect is shown by the crystal?

(ii) How is the density of the crystal affected by this defect?

 (iii) What type of ionic substances shows such defect? 

1953 Views

6.

Calculate the mass of compound (molar mass = 256 g mol-1) to be dissolved in 75 of benzene to lower its freezing point by 0.48 K (Kf= 5.12 kg mol-1 )

3867 Views

7.

Define an ideal solution and write one of its characteristics.

1638 Views

8.

Write two differences between 'order of reaction' and 'molecularity of reaction?

1047 Views

Advertisement
9.

Outline the principles behind the refining of metals by the following methods:

Zone refining method

968 Views

Advertisement

10.

Outline the principles behind the refining of metals by the following methods:

Chromatographic method 


Chromatography method:

Chromatography is the technique used for separation of the components of a mixture that are soluble in the same solvent and are differently adsorbed on an adsorbent. This technique was first used for separation of colours and hence, the name. There are two phases in chromatography - the stationary phase and the mobile phase. The components of the mixture are absorbed differently in the stationary phase, thus leading to their separation. There are many different types of chromatography - paper chromatography, thin-layer chromatography, gas chromatography etc. 

771 Views

Advertisement
Advertisement