Match List I with List II (A) Slaked lime (I) NaOH (B) Dead burnt...

(A) Slaked lime: Calcium oxide is a white amorphous solid. It has a melting point of 2870 K. On exposure to the atmosphere, it absorbs moisture and carbon dioxide.

$CaO + {H}_{2}O \to Ca ( OH{)}_{2}$

$CaO + {CO}_{2} \to {CaCO}_{3}$

The addition of a limited amount of water breaks the lump of lime. This process is called slaking of lime.

(B) Dead burnt plaster: Calcium sulphate is a hemihydrate of calcium sulphate. It is obtained when gypsum, ${CaSO}_{4} . 2{H}_{2}O$ is heated at 393K.

$2 ( {CaSO}_{4} . 2{H}_{2}O ) \to 2 ( {CaSO}_{4} ) . {H}_{2}O + 3{H}_{2}O$

Above 393 K, no water of crystallisation is left and anhydrous calcium sulphate, ${CaSO}_{4}$ is formed. This is known as ‘dead burnt plaster’.

(C) Caustic soda: Sodium hydroxide (caustic soda) $NaOH$ is generally prepared commercially by the electrolysis of sodium chloride in Castner-Kellner cell. A brine solution is electrolysed using a mercury cathode and a carbon anode. Sodium metal discharged at the cathode combines with mercury to form sodium amalgam.

(D) Washing soda: Sodium carbonate is a white crystalline solid which exists as a decahydrate, ${Na}_{2}{CO}_{3} . 10{H}_{2}O$. This is also called washing soda. It is readily soluble in water.

So, the correct matching is (A)-II, (B)-IV, (C)-I, (D)-III.