1994 年

Which of the following is NOT a suitable method of preparation ?

The formula of hydrated magnesium sulphate crystals is MgSO₄ • xH₂O. When 3.80 g of the hydrated crystals are heated, 2.00 g of anhydrous magnesium sulphate are produced. What is the value of x ? (Relative atomic mass: H = 1.0, O = 16.0, Mg = 24.0, S = 32.0)

Which of the following substances can turn an acidified solution of potassium permanganate colourless ?

X is a synthetic polymer. On gentle heating, it softens and chars. On strong heating, it burns with an acidic smell. X is probably

A solution of chlorine in tetrachloromethane is shaken with an aqueous solution of a compound X in a test tube. On standing, two layers are formed in test tube and the lower layer is violet in colour. X may be

Direction: Q.22 and Q.23 refer to the following diagram which shows a fractionating column of an oil refinery.

Which of the following fractions is NOT cracked to produce more useful products?

Direction: Q.22 and Q.23 refer to the following diagram which shows a fractionating column of an oil refinery.

Which of the following statements is correct?

Directions: Q.24 and Q.25 refer to the structural formulae of the following three detergents:

Which of the above is/are soapless detergent(s) ?

Directions: Q.24 and Q.25 refer to the structural formulae of the following three detergents:

Which of the following statements concerning these detergents is correct ?

A sulphuric acid solution is titrated against 25.0 cm³ of 3.0 M sodium hydroxide solution. The results of the thermometric titration can be represented by the following graph.