Problem 123
small quantities in the electrolytic reduction of alumina dissolved in fused cryolite \(\left(\mathrm{Na}_{3} \mathrm{AlF}_{6}\right)\) is 1\. as a catalyst 2\. to make the fused mixture very conducting 3\. to lower the temperature of melt 4\. to decrease the rate of oxidation of carbon at the anode (a) 2,3 (b) 1,2 (c) \(2,3,4\) (d) 3,4
Problem 125
The pair of compounds which cannot exist together in aqueous solution is 1\. \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) and \(\mathrm{Na}_{2} \mathrm{HCO}_{3}\) 2\. \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) and \(\mathrm{NaHCO}_{3}\) 3\. \(\mathrm{NaOH}\) and \(\mathrm{NaH}_{2} \mathrm{PO}_{4}\) 4\. \(\mathrm{NaHCO}_{3}\) and \(\mathrm{NaOH}\) (a) \(1,2,3\) (b) 3,4 (c) 1,4 (d) 2,3
Problem 127
When brine solution is saturated with \(\mathrm{NH}_{3}\) and \(\mathrm{CO}_{2}\) a slightly alkaline white sodium salt (A) is formed which has \(\mathrm{pH}\) of nearly 8.4. (A) on heating liberates a gas (B) leaving a highly alkaline residue (C) of \(\mathrm{pH}\) nearly 10 to 11 . Gas (B) is colourless and turns a solution of \(\mathrm{Ca}(\mathrm{OH})_{2}\) milky. Identify (B). (a) \(\mathrm{Na}_{2} \mathrm{CO}_{3}\) (b) \(\mathrm{NaHCO}_{3}\) (c) \(\mathrm{Na}_{2} \mathrm{~S}\) (d) \(\mathrm{Na}_{2} \mathrm{SO}_{4}\)
Problem 128
Consider the following statements: 1\. Cs ion is more highly hydrated than other alkali metal ions 2\. Among the alkali metals \(\mathrm{Li}, \mathrm{Na}, \mathrm{K}\) and \(\mathrm{Rb}\), \(\mathrm{Li}\) has the higher melting point 3\. Among the alkali metals, only Li form a stable nitride by direct combination (a) 1 and 3 are correct (b) 2 and 3 are correct (c) 1,2 and 3 are correct (d) 1 and 2 are correct
Problem 129
Metal \(X\) on heating in nitrogen gas gives Y.Y on treatment with \(\mathrm{H}_{2} \mathrm{O}\) gives a colourless gas which when passed through \(\mathrm{CuSO}_{4}\) solution gives a blue colour. Y is (a) \(\mathrm{MgO}\) (b) \(\mathrm{Mg}\left(\mathrm{NO}_{3}\right)_{2}\) (c) \(\mathrm{Mg}_{3} \mathrm{~N}_{2}\) (d) \(\mathrm{NH}_{3}\)
Problem 130
Highly pure dilute solution of sodium in liquid ammonia 1\. shows blue colour 2\. exhibits electrical conductivity 3\. produces sodium amide 4\. produces hydrogen gas (a) 1,2 (b) \(1,2,3\) (c) \(2,3,4\) (d) all of these
Problem 131
Out of the following metals, those that cannot be obtained by electrolysis of the aqueous solution of their salts are 1\. \(\mathrm{Ag}\) 2\. \(\mathrm{Mg}\) 3\. Cu 4\. Al (a) 2,4 (b) 2,3 (c) 1,4 (d) all
Problem 132
When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water the sodium ions are exchanged with 1\. \(\mathrm{H}^{+}\)ions 2\. \(\mathrm{Ca}^{2+}\) ions 3\. \(\mathrm{SO}_{4}^{-2}\) ions 4\. \(\mathrm{Mg}^{2+}\) ions (a) 2,4 (b) \(1,2,3\) (c) \(2,4,5\) (d) all are correct
Problem 133
Match the following: List-I List-II 1\. Beryl (i) \(\mathrm{KCl} \cdot \mathrm{MgCl}_{2} .6 \mathrm{H}_{2} \mathrm{O}\) 2\. Carnalite (ii) \(\mathrm{MgCO}_{3}\) 3\. Asbestos (iii) \(3 \mathrm{BeO} \cdot \mathrm{Al}_{2} \mathrm{O}_{3} \cdot 6 \mathrm{SiO}_{2}\) 4\. Magnesite (iv) \(\mathrm{Ca}_{2} \mathrm{Mg}_{5} \mathrm{Si}_{8} \mathrm{O}_{22}(\mathrm{OH})_{2}\) (v) \(\mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) The correct matching is: \(\begin{array}{lll}1 & 2 & 3\end{array}\) 4 (a) (iii) (iv) (i) (ii) (b) (iv) (iii) (ii) (i) (c) (iii) (i) (iv) (ii) (d) (iii) (i) (ii) (iv)
Problem 134
Select the correct statement(s): (a) \(\mathrm{BaSO}_{4}\) is soluble in water (b) \(\mathrm{Ba}(\mathrm{OH})_{2}\) is soluble in water (c) \(\mathrm{MgSO}_{4}\) is soluble in water (d) \(\mathrm{CaF}_{3}\), is soluble in water
