Question

Answer the following questions from 1 to 15. Each questions carries 1 score
(A) Choose the correct answer in the following.
1. Which of the following is not the property of crystalline solids?
(a) Definite geometry. b) Sharp melting point
C) Isotropy. d) Sharp cut
2 How much charge is required to 1 mole of AP to Al?
@) 2F. (b) 1F. ©) 3F. () 5 F
3. Which of the following colligative properties can provide molar mass of proteins with
greatest precision?
(a) Depression in freezing point (b) osmotic pressure
(c) Relative lowering of vapour pressure
(d) Elevation in boiling point
4. For a intravenous injections, only solutions with freezing point depression equal to
that of 0.9% NaCl is used. Why?
(a) Blood is isotonic with 0.9% NaCl solution
(b) Blood is hypertonic with 0.9% NaCl solution
(c) Blood is hypotonic with 0.9% NaCl solution
(d) None of these
5. Given the equation, 2Cr + 3 Pb* ---> 2Cr (23) + 3 Pb(s) which is the correct
reduction half reaction?
(a) Cr(s)
> Cro (22) + 3e
(b) Pb
Pb. + 2e
(c) Cris + 3e -> Cr3+
(d) Pb+ 2e -> Pb.
(8) Fill in the blanks
6. The number of tetrahedral void for a lattice consisting of N atoms is
7. The concentration term used when the solute is present in trace amount is
8. The electrode potential of standard hydrogen electrode is.
9. Molar conductivity of an electrolyte - with decrease in concentration or
increase in dilution
10. Corrosion is a
phenomenon​

Answer 1

Explanation:

1) isotropy

Crystalline solids are anisotropic in nature, that is, some of their physical properties like electrical resistance or refractive index show different values when measured along different directions in the same crystals. This arises from different arrangement of particles in different directions. Since the arrangement of particles is different along different directions, the value of the same physical property is found to be different along each direction.

2) 3F

3) osmotic pressure

the osmotic pressure can be used to obtain accurate estimates of molar masses of solutes dissolved in solution. It is more useful, for example, to determine the molar mass of a protein through the osmotic pressure than by trying to measure the pressure of a protein gas!

4) blood is isotonic with 0.9% on NaCl.

The intracellular fluid of erythrocytes is a solution of salts, glucose, protein and hemoglobin. A 0.9% NaCl solution is said to be isotonic: when blood cells reside in such a medium, the intracellular and extracellular fluids are in osmotic equilibrium across the cell membrane, and there is no net influx or efflux of water.

5)------

6) to calculate the number of Tetrahedral Voids in a lattice. Here if the number of spheres (i.e. unit cells) is said to be “n”, then the number of voids will be twice as many. So the number of tetrahedral voids will be “2n”.

7) here solute present in trace amount, and solvent in excess so it is a dilute solution.

8) to form a basis for comparison with all other electrode reactions, hydrogen's standard electrode potential (E0) is declared to be zero volts at any temperature.

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

Molar conductivity of a solution at a given concentration is the conductance of volume V of a solution containing one mole of electrolyte kept between two electrodes with an area of cross-section A and distance of unit length.Ʌm = К/c

c = n/V

Here,

n= no. of moles

V = volume

c = concentration in moles per volume

c = concentration in moles per volumeК = specific conductivity

c = concentration in moles per volumeК = specific conductivityɅm = molar conductivity

Ʌm = KV/n

So as volume increases with dilution (decrease in concentration)

So molar conductivity increase with dilution.

NOTE :

• Specific conductivity or conductivity of an electrolytic solution at any given concentration is the conductance of unit volume of solution kept between two platinum electrodes with a unit area of cross-section and at a distance of unit length.

Conductivity decreases with decrease in concentration as the number of ions per unit volume that carry the current in a solution decrease on dilution.

10) Corrosion is a natural process that converts a refined metal into a more chemically stable form such as oxide, hydroxide, or sulfide. It is the gradual destruction of materials (usually a metal) by chemical and/or electrochemical reaction with their environment.