Science (English Medium) Class 12 - CBSE Question Bank Solutions

Schottky defect defines imperfection in the lattice structure of ____________.

Which is not correct about the Schottky defects?

Assertion: No compound has both Schottky and Frenkel defects.

Reason: Both defects change the density of the solid.

Assertion: Due to Frenkel defect, there is no effect on the density of the crystalline solid.

Reason: In Frenkel defect, no cation or anion leaves the crystal.

0.450 g of urea (mol. wt. 60) in 22.5 g of water show 0.170°C of elevation in boiling point. The molal elevation constant of water is:

Exactly 1 g of urea dissolved in 75 g of water gives a solution that boils at 100.114°C at 760 torrs. The molecular weight of urea is 60.1. The boiling point elevation constant for water is:

Most acidic oxide among the following is:

NH₃ gas is dried over:

Iodide of Millon's base is ____________.

In the following sequence of the reactions, what is D?

The pesticide DDT slowly changes to __________.

Phosgene is a common name for ____________.

In which of the following conversions, phosphorus pentachloride is used as the reagent?

Chloroform and conc. HNO₃ reacts to produce ____________.

B.H.C. is used as an ____________.

Gammexane is ____________.

Among the following, insecticide is:

Which has the lowest boiling point at 1 atm pressure?

People add sodium chloride to water while boiling eggs. This is to ____________.

The molal elevation constant depends upon ____________.