Physical Chemistry MCQ with Answers

101) An element (atomic mass = 100 gm⁄mol) having bcc structure, has unit cell edge 400 pm. The density of the element is:

Answer is:

5.188 gm⁄cc

102) The appearance of colour in solid alkali metal halides is generally due to:

Answer is:

F−center

Explanation:

When the electron takes the place of an anion in a crystal, then a non−stoichiometry arises. This extra electron is delocalised and when it absorbs light, it gets excited from ground state to higher energy state, and the crystal thus, appeared coloured. The site at which this extra electron is placed is called the F−center.

103) Which of the following compounds has an antifluorite structure?

Answer is:

K₂O

104) In a solid AB, having the NaCl structure, A atoms occupy the corners of the cubic unit cell. If all the face centered atoms along one of the axes are removed, then the resultant stoichiometry of the solid is:

Answer is:

A₃B₄

105) The yellow colour of ZnO and conducting nature produced upon heating is due to:

Answer is:

All of these

Explanation:

The yellow colour of ZnO and conducting nature produced upon heating is due to
* Metal excess defects due to interstitial cation
* Extra positive ions present in an interstitial site
* Trapped electrons

101) An element (atomic mass = 100 gm⁄mol) having bcc structure, has unit cell edge 400 pm. The density of the element is:

5.188 gm⁄cc

102) The appearance of colour in solid alkali metal halides is generally due to:

F−center

103) Which of the following compounds has an antifluorite structure?

K2O

104) In a solid AB, having the NaCl structure, A atoms occupy the corners of the cubic unit cell. If all the face centered atoms along one of the axes are removed, then the resultant stoichiometry of the solid is:

A3B4

105) The yellow colour of ZnO and conducting nature produced upon heating is due to:

All of these

K₂O

A₃B₄