Question

Given below are two statements : one is labelled as assertion $\mathrm{A}$ and the other is labelled as reason $\mathrm{R}$ ;

Assertion $\mathrm{A}$: During the boiling of water having a temporary hardness,$\mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2$ is converted to ${\mathrm{MgCO}}_{3.}$

Reason $\mathrm{R}$ : The solubility product of $\mathrm{Mg}{\left(\mathrm{OH}\right)}_2$is greater than that of ${\mathrm{MgCO}}_{3.}$

In the light of the above statements, choose the most appropriate answer from the option given below.

• A. $\mathrm{A}$ is false $\mathrm{R}$ is true
• B. Both $\mathrm{A}$ and $\mathrm{R}$ are true and $\mathrm{R}$ is the correct explanation of $\mathrm{A}$.
• C. Both $\mathrm{A}$ and r are true but $\mathrm{R}$ is not the correct explanation of $\mathrm{A}$
• D. $\mathrm{A}$ is true but $\mathrm{R}$ is false

Answer 1

The correct option is A

$\mathrm{A}$ is false $\mathrm{R}$ is true

Answer (A)

Explanation for correct option:

$$\begin{gathered} \mathrm{R})\mathrm{Ca}{\left({\mathrm{HCO}}_3\right)}_2\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{CO}}_2 \\ {{\mathrm{CO}}_3}^{2-}\to \mathrm{Lest}\mathrm{soluble}\to {\mathrm{OH}}^{-} \end{gathered}$$

Here heat hydration is less soluble.

Explanation for incorrect option:

$\mathrm{A})\mathrm{Mg}{\left({\mathrm{HCO}}_3\right)}_2\to \mathrm{Mg}{\left(\mathrm{OH}\right)}_2\downarrow +{\mathrm{CO}}_2$

Here Statement A is wrong R is right.Hence option (A) is correct.