An element with density 2.8 g cm−3 forms of the f.c.c. unit cell with edge length 4 X10−8 cm. Calculate the molar mass of the element.
(Given: NA = 6.022 X 1023 mol −1)
(i) What type of non-stoichiometric point defect is responsible for the pink colour of LiCl?
(ii) What type of stoichiometric defect is shown by NaCl?
OR
How will you distinguish between the following pairs of terms:
(i) Tetrahedral and octahedral voids
(ii) Crystal lattice and unit cell.
State Kohlrausch's law of independent migration of ions. Why does the conductivity of a solution decrease with dilution?
Kohlrausch's law of independent migration of ions: It states that the limiting molar conductivity of an electrolyte can be represented as the sum of the individual contributions of its anion and cation.
A conductivity of a solution decreases with dilution because it leads to decrease in a number of ions per unit volume.
For a chemical reaction R → P, the variation in the concentration (R) vs. time (t) plot is given as,
(i) Predict the order of the reaction.
(ii) What is the slope of the curve?
Explain the principle of the method of electrolytic refining of metals. Give one example.