Which of the following options are correct? (i) Cast iron is obtained by remelting pig iron with scrap iron and coke using hot air blast.

correct answer is (D) p.

(ii), (iii) (ii) Micelle formation by soap in aqueous solution occurs above a particular concentration. (iii) On dilution of soap solution micelles may revert to individual ions.

(i), (iv) (i) Fe2O3 + 3CO → 2Fe + 3CO2   (iv) CaO + SiO2 → CaSiO3

Fe2O3 + 3C → 2Fe + 3CO Limestone is added as flux and sulphur, silicon and phosphorus change to their oxides and pass into the slag.

Haematite Fe2O3 + 3C → 2Fe + 3CO

(a) Acceleration due to gravity decreases with increasing altitude. (c) Acceleration due to gravity increases with increasing latitude.

(i), (iii) (i) d2sp3 hybridisation (iii) paramagnetic

(ii) O2– < O2 < O2+

(i) The enthalpy of two moles of ZnO is less than the total enthalpy of two moles of Zn and one mole of oxygen by 693.8 kJ. (iii) 693.8 kJ mol–1 energy...

(i) ΔGΘ = 0 Justification : ΔGΘ = – RT lnK At the stage of half completion of reaction [A] = [B], Therefore, K = 1. Thus, ΔGΘ = 0