Metallurgy — Chemistry STD 10 — Question

State one relevant observation for each of the following :
(i) Copper is heated with concentrated nitric acid in a hard glass test tube.
(ii) Ammonia gas is burnt in an atmosphere of excess of oxygen.
(iii) Concentrated nitric acid is reacted with sulphur.

Give composition and uses of the following alloys. Mention the reason for its use.
Solder

(a) Name the process used for the large scale manufacture of sulphuric acid.
(b) Which property of sulphuric acid accounts for its use as a dehydrating agent?
(c) Concentrated sulphuric acid is both, an oxidising agent and a non-volatile acid. Write one equation each to illustrate the above mentioned properties of sulphuric acid.

(a) What do you understand by the term concentration of ore?
(b) Name three processes used for the concentration of ore and name one specific ore which can be concentrated by the named process.

Explain the following briefly:
Sodium chloride dissolves in water but carbon tetra chloride is insoluble in water.

Three different electrolytic cells, A,B, and C are conncted in separate circuits. Electrolytic cell A contains sodium chloride solution. When the circuit is completed a bulb in the circuit glows brightly. Electrolytic cell B contains acetic acid solution and in this case the bulb in the circuit glows dimly. The electrolytic cell C contains sugar solution and the bulb does not glow. Give a reason for each of these observations.

An organic compound with vapour density = 94 contains C = 12.67%, H = 2.13%, and Br = 85.11%. Find the molecular formula.
(Atomic mass : C = 12, H = 1, Br = 80}