Question

Select the correct statement(s).

• A. Passage of sulphur dioxide or of hydrogen sulphide (not in excess) in to a solution of an iodate acidified with dilute hydrochloric acid, liberates iodine
• B. Phosphate rock, $C{a}_3(P{O}_4{)}_2$ on heating with sand and coke in electric furance at $1400-{1500}^{o}C$ yields dimeric phosphorus pentaoxide
• C. Reaction of $H_{2}S$ on aqueous solution of sodium sulphite yields sodium thiosulphate
• D. Sodium hypophosphite on warming with copper sulphate solution gives red precipitate of copper (I) hydride

Answer 1

Answer: (A), (C), (D)

(A) $2I{O}_3^{-}+5H_{2}S{O}_3\to I_2+5S{O}_4^{2-}+O{H}^{+}+H_{2}O;2I{O}_3^{-}+5H_{2}S+2H^{+}\to I_2+5S+6H_{2}O$
(B) $2C{a}_3(P{O}_4{)}_2+6Si{O}_2+10C\stackrel{1400-{1500}^{o}C}{\to }6CaSi{O}_3+10CO+P_4$.
(C) $2H{S}^{-}+4HS{O}_3^{-}\to 3S_2{O}_3^{2-}+3H_{2}O$
(D) $3H_{2}P{O}_2^{-}+4C{u}^{2+}+6H_{2}O\to 4CuH\downarrow \left(red\right)+3H_{2}P{O}_4+5H^{+}$