71.

Glass is a

• liquid

• coiloid

• non-crystalline amorphous solid

• crystalline solid

A homogeneous mixture contains two liquids are they separated?

• By filtration

• By evaporation

• By distillation

• By condensation

Which one of the following elements forms highest numher of compounds?

• Oxygen

• Hydrogen

• Chlorine

• Carbon

Which one of the following elements corrodes rapidly?

• Aluminium

• Iron

• Zinc

• Silver

20 g of common salt is dissolved in 180 g of water. What is the mass percentage of the salt in the solution?

• 5 %

• 9 %

• 10 %

• 15 %

The valency of an element depends upon the

• total number of protons in an atom

• mass number of an atom

• total number of neutrons in an atom

• total number of electrons in the outer most shell of an atom

Match List-I with List-II and select the correct answer using the codes given below the Lists:

List I (Noble gas): (a) Argon, (b) Neon, (c) Krypton, (d) Xenon

List II (Use): (1) In lights for advertising display, (2) Airport landing lights and in light houses, (3) Light in photographer's flash gun, (4) In tungsten filament to last longer

• (a) - 3, (b) - 1, (c) - 2, (d) - 4

• (a) - 3, (b) - 2, (c) - 1, (d) - 4

• (a) - 4, (b) - 2, (c) - 1, (d) - 3

• (a) - 4, (b) - 1, (c) - 2, (d) - 3

Why is it difficult to measure the coefficient of expansion of a liquid than solid?

• Liquids tend to evaporate at all temperatures

• Liquids conduct more heat

• Liquids expand too much when heated

• Their containers also expand when heated

Radon is

• an inert gas

• an artificial fibre

• an explosive

• a metal

The chemical name of baking soda is

• Na₂CO₃

• NaHCO₃

• CaCO₃

• NaOH