Solid State

Which amongst the following options is the correct relation between change in enthalpy and change in internal Energy?

A compound is formed by two elements A and B. The element B forms cubic close packed structure and atoms of A occupy 1/3 of tetrahedral voids. If the formula of the compound is A?B?, then the value of x + y is in option

Choose the correction option for the total pressure (in atm.) in a mixture of 4g O₂ and 2g H₂ confined in a total volume of one litre at 0°C is:

The molar conductance of NaCl, HCl and CH?COONa at infinite dilution are 126.45, 426.16 and 91.0 cm² mol¯¹ respectively. The molar conductance of CH?COOH at infinite dilution is. Choose the right option for your answer.

Copper crystallises in fee unit cell with cell edge length of 3.608 × 10^-8 cm. The density of copper is 8.92 g cm^-3. Calculate the atomic mass of copper.

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A): In a particular point defect, an ionic solid is electrically neutral, even if few of its cations are missing from it unit cells.
Reason (R): In an ionic solid, Frenkel defect arises due to dislocation of cation from its lattice site to interstitial site, maintaining overall electrical neutrality.

In the light of the above statements, choose the most appropriate answer from the options given below:

A certain element crystallises in a bcc lattice of unit cell edge length 27 Å . If the same element under the same conditions crystallises in the fcc lattice, the edge length of the unit cell in Å will be ___________. (Round off to the nearest Integer).

[Assume each lattice point has a single atom] [Assume √3 = 1.73, √2 = 1.41]

Ga (atomic mass 70u) crystallizes in a hexagonal close packed structure. The total number of voids in 0.581 g of Ga is __________ *10²¹. (Round off to the nearest integer).
[Given: N? = 6.023 *10²³]

A hard substance melts at high temperature and is an insulator in both solid and in molten state. This solid is most likely to be a/ an:

In order to prepare a buffer solution of pH 5.74, sodium acetate is added to acetic acid. If the concentration of acetic acid in the buffer is 1.0 M, the concentration of sodium acetate in the buffer is _____ M. (Round off to the nearest integer).
[Given: pKa (acetic acid) = 4.74]