A hydrocarbon which is a greenhouse gas is:

1. Acetylene
2. Ethylene
3. Ethane
4. Methane

Fill in the blanks with the choices given in brackets:

(i) Conversion of ethanol to ethene by the action of concentrated sulphuric acid is an example of …………… (dehydration/dehydrogenation/dehydrohalogenation)

(ii) When sodium chloride is heated with concentrated sulphuric acid below 200°C, one of the products formed is …………… (sodium hydrogen sulphate / sodium sulphate / chlorine)

(iii) Ammonia reacts with excess chlorine to form …………… (nitrogen / nitrogen trichloride / ammonium chloride)

(iv) Substitution reactions are characteristic reactions of …………… (alkynes / alkenes / alkanes)

(v) In Period 3, the most metallic element is …………… (sodium / magnesium / aluminium)

State one observation for each of the following:

(i) Concentrated nitric acid is reacted with sulphur.

(ii) Ammonia gas is passed over heated copper (II) oxide.

(iii) Copper sulphate solution is electrolysed using copper electrodes.

(iv) A small piece of zinc is added to dilute hydrochloric acid.

(v) Lead nitrate is heated strongly in a test tube.

(i) Calculate:

1. The number of moles in 12g of oxygen gas. [O = 16]

2. The weight of 10²² atoms of carbon.

[C = 12, Avogadro’s No. = 6 x 10²³]

(ii) Molecular formula of a compound is C₆H₁₈O₃. Find its empirical formula.