Available Answers

1. 1.

   Select the correct answers from A, B, C, D & E for each statements given below:-
   A. Chalk   B. Oxygen    C. Silicon     D. Bromine     E. Nitrous Oxide

   1. An element present in the earth's crust, atmosphere & human body.
   2. The chemical name for dinitrogen oxide [N₂O]
   3. A compound containing carbon, oxygen & calcium.
   4. A metalloid.
   5. A non-metal which exists in the liquid state.
2. 2.

   Select the correct answer from the choice in bracket:

   1. The least reactive material. [magnesium/silver/copper]
   2. The positively charged particle of an atom. [electron/proton/neutron]
   3. The formula of caustic soda. [KOH/Ca(OH)₂, NaOH]
   4. The ideal method to separate iodine & KCl. [sublimation/evaporation/distilliation]
   5. A homogeneous mixture. [brass/dust in air/chalk & water]
3. 3.

   Match the ideal method of separation of components in a mixture in List I with the appropriate process in List II.

   1. Sand from a mixture of sand and water: A. Separating funnel
   2. Kerosene from a mixture of kerosene and water: B. Sublimation
   3. Alcohol from a mixture of methyl alcohol and water: C. Filtration
   4. Napthalene from a mixture of naphthalene and lead chloride: D. Distillation
   5. Pure water from impure water: E. Fractional distillation
4. 4.

   If fractional distillation is carried out using a liquid-liquid mixture,one liquid will remain in the flask & the other will be collected from the receiver. Give reasons.

5. 5.

   Name the following:

   1. The non-sublimate solid from a mixture of iodine & potassium nitrate.
   2. The heavier liquid component from mercury & water.
   3. The lower boiling point component from methyl alcohol & water.
   4. The compound containing one atom of sulphur & two atoms of oxygen.
   5. An acid whose formula is H₂CO₃
6. 6.

   Differentiate between the terms elements, compounds & mixtures with suitable examples.