Question

Assertion :As both calcium and sulphate carry two positive charges the formula of calcium sulphate is $C{a}_2(S{O}_4{)}_3$ Reason: Calcium sulphate is a compound formed by combination of calcium and sulphate ions

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is D Both Assertion and Reason are incorrect

(I) Chemical formula represents number of atoms of elements present in a compound. Chemical formula is given by symbol of element and number of atoms of the element.

$C{a}_2(S{O}_4{)}_3$ is overall neutral.

$\Rightarrow 2\times \left(2\right)+3\times (-2)=0$ [$Ca⟶+2$ valency, $S{O}_4⟶-2$ valency]

$\Rightarrow 4-6=0$

$\therefore -2$ charge would be more on $C{a}_2(S{O}_4{)}_3$ if this chemical formula of calcium sulphate is assumed.

Correct chemical formula is given as:-

(Refer to Image)

(II) Insoluble anhydrite $CaS{O}_4$ has been commercially manufactured by the calcination of gypsum rock at a relatively high temperature.

(i) $\underset{gypsum}{CaS{O}_4.2H_{2}O}\stackrel{110-{130}^{o}C}{\to }\underset{Plaster}{CaS{O}_{4}1/2H_{2}O}\stackrel{130-{200}^{o}C}{\to }\underset{Hexagonal}{CaS{O}_4}$

(ii) $\underset{CalciumCarbonate}{CaC{O}_3}+\underset{Acid}{H_{2}S{O}_4}⟶\underset{CalciumSulphate}{CaS{O}_4}+H_{2}O+C{O}_2\uparrow$

Hence, both statement are incorrect.