Calculate the molecular weights of the following compounds.
`{:((i),H_(2)SO_(4),(ii),HCl,(iii),NaCl),((iv),HNO_(3),(v),MgCl_(2),(vi),Na_(2)CO_(3)),((vii),Na_(2)SO_(4),(viii),SO_(2),(ix),CO_(2)),((x),O_(3),,,,):}`

Presence of which of the forcoming compounds makes water hard ? Na_(2)SO_(4),Ca(HCO_(3))_(2),MgCl_(2),Na_(2)CO_(3),CaSO_(4),KCl,NaHCO_(3),MgSO_(4),CaCl_(2)

Calculate the oxidation number of each sulphur atom in the following compounds. (a) Na_(2)S_(2)O_(3) " " (b) Na_(2)S_(4)O_(6) " " ( c) Na_(2)SO_(3) " " (d) Na_(2)SO_(4)

Na_(2)C_(2)O_(4)+H_(2)SO_(4)(Conc.) to Na_(2)SO_(4)+CO+CO_(2)

Na_(2)CO_(3), " " Fe_(2)(SO_(4))_(3), " " FeSO_(4).7H_(2)O

Write the empirical formulae of the following compounds. (i) C_(6)H_(6) (ii) Na_(2)CO_(3) (iii) C_(6)H_(12)O_(6) (iv) H_(2)O_(2) (v) CH_(3)COOH (vi) CuSO_(4)

Calculate the oxidation number of suplhur in the folowing molecules and ions: (i) H_(2)SO_(4) , (ii) Na_(2)SO_(4), (iii) SO_(4)^(2-), (iv)S_(2)O_(4)^(2-)

Write the empirical formula of the compounds having the molecular formulae : (i) C_(6)H_(6) , (ii) C_(6)H_(12) , (iii) H_(2)O_(2) , (iv) Na_(2)CO_(3) , (v) B_(2)H_(6) , (vi) N_(2)O_(2) , (vii) H_(3)PO_(4) , (viii) Fe_(2)O_(3) , (ix) C_(2)H_(2) , (x) N_(2)O_(5)