(a) Define molar conductivity of a solution and explain how mola

Subject

Chemistry

Class

CBSE Class 12

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 Multiple Choice QuestionsShort Answer Type

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21.

(a) Define molar conductivity of a solution and explain how molar conductivity changes with a change in concentration of solution for a weak and a strong electrolyte.

(b) The resistance of a conductivity cell containing 0.001 M KCl solution at 298 K is Ω 1500 . What is the cell constant if the conductivity of 0.001 M KCl solution at 298 K is 0.146x10-3 S cm-1?


Molar conductivity of a solution at a given concentration is the conductance of volume V of a solution containing 1 mole of the electrolyte kept between two electrodes with the area of cross-section A and distance of unit length.


Molar conductivity increases with a decrease in concentration. This is because the total volume V of the solution containing one mole of the electrolyte increases on dilution.

Variation of molar conductivities with dilution:

For strong electrolytes, molar conductivity slowly increases with dilution.

For weak electrolytes, molar conductivity increases steeply on dilution, especially near lower concentrations. The variation of  with  for strong and weak electrolytes is shown in the following plot:


b) Given,

 Conductivity, k = 0.146 x 10-3 S cm-1

Resistance, R = 1500 ohm

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22.

(a) Complete the following chemical reactions equations:

(i) P4+SO2Cl-->

(ii) XeF6+H2O -->

(b) Predict the shape and the asked angle (90° or more or less) in each of the following cases:

 (i)  and the angle O - S - O

(ii) ClF3 and the angle F - Cl - F

(iii) XeF2 and the angle F - Xe - F

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23.

Complete the following chemical equations:

(i) NaOH+Cl-->

(ii) XeF4+O2F2--->

(b) Draw the structures of the following molecules:

(i) H3PO2

(ii) H2S2O7

(iii) XeOF4

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24.

Give the IUPAC name of the following compound.


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25.

Draw the structural formula of a 2-methylpropan-2-ol molecule.

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26.

Arrange the following compounds in an increasing order of their reactivity in nucleophilic addition reactions: ethanol, propanal, propanone, butanone.

 

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27.

Define the term, ‘homopolymerisation’ giving an example.

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28.

What is meant by (i) peptide linkage (ii) biocatalysts?

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29.

Write any two reactions of glucose which cannot be explained by the open chain structure of glucose molecule.

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30.

Draw the structure of the monomer for each of the following polymers:

(i) Nylon 6

(ii) Polypropene

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