Which of the following is used to study the arrangement of particles in crystal lattices?

• A) Alpha-particles
• B) Beta-particles
• C) Gamma-rays
• D) X-rays

I. It has a varied composition from one place to another. II. It constituents can be separated by physical means. III. It contains unreactive noble gases Which of the above shows that air is a mixture?

• A) I and II only
• B) II and III only
• C) I and III only
• D) I, II and III

The electronic configuration of Mg 2+ is

• A) ls 22s 22P 63s23P2
• B) Is22s22P6
• C) ls22s22p63s2
• D) ls22s22P4

Ethanol reacts with concentrated tetraoxosulphate (V) acid at a temperature above 170 oC to form

• A) ethanone
• B) ethene
• C) ethyne
• D) ethanal

The chemicals used to soften hard water involves the addition of

• A) insoluble sodium compounds which from soluble solutions of calcium and magesium
• B) solube soudium compounds which from soluble solutions of calcium and magnesium ions
• C) solube sodium compounds which from insoluble precipitates of calcium and magnesium ions
• D) insoluble precipitates of calcium and magnesium ions

Carbohydrates are large molecules with the molecular formula C x (H2O)y. In which of the following pairs is x not equal to y?

• A) glucose and starch
• B) maltose and starch
• C) sucrose and fructose
• D) maltose and starch

L . Evaporation. ll. Sublimation. lll. Diffusion. IV. Brownian motion. Which of the above can correctly be listed as evidences for the

• A) I and lll only
• B) ll and lV only
• C) l, ll and lll only
• D) l, ll, lll and lV

Potassium trioxochlorate (V)has a solubility of 1.5 mol dm -3 at 45 oC.On cooling this solution to a temperature of 20 oC, the solubility was found to be 0.5 mol dm -3. What mass of KCIO 3 was crystalized out? [K = 39, Cl = 35.5 O =16].

• A) 1.00g
• B) 10.00g
• C) 12.25g
• D) 122.50g

Commercial bleaching can be carried out using

• A) sulphur (IV) oxide and ammonia
• B) hydrogen sulphide and chlorine
• C) chlorine and sulphur (IV) oxide
• D) ammonia and chlorine

Chlorination of water for town supply is carried out to

• A) make the water colourless
• B) remove germs from the water
• C) make the water tastedful
• D) remove odour from the water