How many statements are correct? (i) Glauber's salt is N a 2 S O 4 ⋅ 10 H 2 O . (ii) Epsom salt is MgS O 4 ⋅ 7 H 2 O . (iii) Baryta water is a suspension of barium hydroxide in water. (

Question

How many statements are correct?

(i) Glauber's salt is $N a_{2} S O_{4} \cdot 10 H_{2} O$ .

(ii) Epsom salt is $MgS O_{4} \cdot 7 H_{2} O$ .

(iii) Baryta water is a suspension of barium hydroxide in water.

(iv) The ionic mobilities in water follow $L i^{+} > N a^{+} > K^{+}$ .

(v) The magnitude of the hydration enthalpy is greatest for $L i^{+}$ among alkali-metal cations.

(vi) In the Castner-Kellner cell, sodium is liberated at the mercury cathode as sodium amalgam.

(vii) Anhydrous $MgC l_{2}$ is obtained simply by heating $MgC l_{2} \cdot 6 H_{2} O$ strongly in air.

TestHub · Accepted Answer

Statements i and ii give the correct hydrated salts.

Statement iii is false: baryta water is a clear solution of barium hydroxide, not a suspension.

Statement iv is false: strong hydration makes lithium ions less mobile

the order for these ions is $L i^{+} < N a^{+} < K^{+}$ .

Statement v is true: lithium ions have the most negative hydration enthalpy, hence the greatest magnitude.

Statement vi correctly describes sodium-amalgam formation at the mercury cathode.

Statement vii is false: heating hydrated magnesium chloride in air causes hydrolysis.

Dry hydrogen chloride is used to suppress hydrolysis when preparing the anhydrous chloride.

Correct statements: i, ii, v and vi.

Answer: 4.

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