Liquefied air is mainly a mixture of nitrogen and oxygen which can be separated into its components by fractional distillation (Boiling point of nitrogen is 196°C, Boiling point of oxygen is 174°C)

(a) Name the fraction which distills over first. Give the reason for your answer.

(b) Give another industrial application of fractional distillation as a separation technique.

Hydration of ions in solution is associated with

• A) absorption of heat
• B) reduction of heat
• C) conduction of heat
• D) liberation of heat

Soap lather is an example of a colloid in which a

• A) liquid is dispersed in gas
• B) solid is dispersed in liquid
• C) gas is dispersed in liquid
• D) liquid is dispersed in liquid

Which of the gases is employed as an anaesthesia?

• A) N 2O
• B) NO2
• C) NH3
• D) NO

The following properties are characteristics of transition elements except

• A. formation of complex ions
• B. fixed oxidation states
• C. formation of coloured compounds
• D. catalytic abilities

Which of the following substances is a non-reducing sugar?

• A. Sucrose
• B. Glucose
• C. Fructose
• D. Maltose

What type of reaction is involved when wood shavings produce a brown gas with concentrated HNO₃

• A. Redox reaction
• B. Destructive distillation
• C. Dehydration
• D. Nutralization

The minimum volume of oxygen required for the complete combustion of a mixture of 10cm³ of CO and 15cm³ of H₂ is

• A) 25.0cm³
• B) 12.5cm³
• C) 10.0cm³
• D) 5.0cm³

Transpiration can be measured with a

• A. photometer
• B. hygrometer
• C. potometer
• D. barometer

Chromatography is used to separate components of mixture which differ in their rates of ?

• A. diffusion
• B. migration
• C. reaction
• D. sedimentation