Action of concentrated sulphuric acid on carbon

Action of dilute hydrochloric acid on sodium sulphide

Preparation of ethane from sodium propionate

Distinguish between the following pairs of compounds using the test given within
brackets:

Iron (II) sulphate and iron (III) sulphate (using ammonium hydroxide)

A lead salt and a zinc salt (using excess ammonium hydroxide)

Sodium nitrate and sodium sulphite (using dilute sulphuric acid)

Dilute sulphuric acid and dilute hydrochloric acid (using barium chloride solution)

Ethane and ethene (using alkaline potassium permanganate solution)

Oxygen oxidises ethyne to carbon dioxide and water as shown by the equation:
$$\ce{2C2H2 + 5O2 -> 4CO2 + 2H2O }$$
What volume of ethyne gas at STP is required to produce ``\pu{8.4 dm3}`` of carbon
dioxide at STP? [H = 1, C = 12, O = 16]

A compound made up of two elements X and Y has an empirical formula ``\ce{X2Y}``. If the
atomic weight of X is 10 and that of Y is 5 and the compound ha a vapour density 25,
find its molecular formula.

State your observation in each of the following cases: