(a) If the valency of carbon is 4 and that of sulphur is 2, write the formula of the compound formed berween carbon and sulphur atoms. Also name the compound.
(b) What is wrong with the statement '1' mole of hydrogen?

Explanation

(a) The formula of compound can be written by exchanging the valencies (cross-over). Therefore, the expected formula is `C_(2)S_(4) or CS_(2)`. The compound is called carbon disulphide.
(b) The statement is not correct. We must always write whether hydrogen is in atomic form or molecular form. The correct statement is q
'1 mole of hydrogen atoms or one mole of hydrogen molecules'.