(a) 1 litre of a mixture of CO and CO₂ is taken. This mixture is passed through a tube containing red hot charcoal. The volume now becomes 1.6 litre. The volumes are measured under the same conditions. Find the composition of the mixture by volume.

(b) A compound contains 28 percent of nitrogen and 72 percent of metal by weight. 3 atoms of metal combine with 2 atoms of N. Find the atomic weight of metal.

A hydrocarbon contains 10.5 g of carbon per gram of hydrogen. 1 litre of the hydrocarbon at 127^oC and 1 atmosphere weighs 2.8 g. Find the molecular formula.

A mixture contains NaCl and unknown chloride MCl.

(i) 1g of this is dissolved in water. Excess of acidified AgNO₃ solution is added to it. 2.567 g of white ppt is formed.

(ii) 1 g of original mixture is heated to 300^oC. Some vapours come out which are absorbed in acidified AgNO₃ solution, 1.341 g of white precipitate was obtained.

Find the molecular weight of unknown chloride.

Find
(i) The total number of neutrons and
(ii) The total mass of neutron in 7 mg of ¹⁴C
(Assume that mass of neutron = mass of hydrogen atom)