Ice has an open structure compared to water due to which it floats on water and occupies a greater volume of space. The open structure of ice is due to _____.

1. 1. Hydrogen bonding
   2. Crystalline nature
   3. Its low density
   4. Solid state of ice

At high altitudes the boiling point of water decreases because _____.

1. 1. Water is cold
   2. Atmospheric pressure is high
   3. Temperature is low
   4. Atmospheric pressure is low

A pressure cooker reduces cooking time because _____.

1. 1. B.P. of water inside the cooker is increased
   2. Heat is more evenly distributed
   3. The high pressure tenderises the food
   4. A longer flame is used

When glycerine is added to a litre of water, which of the following is observed?

1. 1. Water evaporates more easily
   2. The temperature of water increases
   3. The freezing point of water is lowered
   4. The viscosity of water is lowered

Gelatin is often used as an ingredient in the manufacture of ice cream. The purpose of adding gelatin is _____.

1. 1. to stabilise the colloids and prevent crystal growth
   2. to prevent formation of colloidal solution
   3. to increase the bulk
   4. to improve the flavour

The rate of chemical reaction depends on the nature of chemical reactants because _____.

1. 1. Some of the reactants are solid at room temperature
   2. Some of the reactants are coloured
   3. Energy of activation differs from one reactant to another
   4. All of the above

All of the followings are different uses of hydrogen peroxide except _____.

1. 1. Used to prepare organic peroxides
   2. Used to deodour sewers
   3. Used as bleaching agent
   4. Used as fuel in space

When radioactive rays are passed through air or any gas, they cause it to _____.

1. 1. freeze
   2. boil
   3. ionize
   4. evaporate

The elements in the first period of the periodic table are _____.

1. 1. Hydrogen and Helium
   2. Hydrogen, Nitrogen and Oxygen
   3. Hydrogen, Helium and Carbon
   4. Hydrogen, Helium, Nitrogen and Oxygen

Cooling of vapours of some compounds change them directly into solid state. This phenomenon is called _____.

1. 1. 1. Sublimation
      2. Condensation
      3. Evaporation
      4. Crystallisation