Name the following organic compounds:

(i) The compound with three carbon atoms whose functional group is a carboxyl.

(ii) The first homologue whose general formula is C_nH_2n

(iii) The compound that reacts with acetic acid to form ethyl ethanoate

(iv) The compound formed by complete chlorination of ethyne.

Identify the substances italicised : The organic compound which when solidified, forms an ice like mass.

Choose the correct answer from the options: The organic compound having a triple carbon-carbon covalent bond, is

A: C₃H₄
B: C₃H₆
C: C₃H₈
D: C₄H₁₀

State one relevant observation for the following reaction: A piece of sodium metal is put into ethanol at room temperature.