Medium INTEGER +4 / -1 PYQ · JEE Mains 2025

Some $\mathrm{CO}_2$ gas was kept in a sealed container at a pressure of 1 atm and at 273 K . This entire amount of $\mathrm{CO}_2$ gas was later passed through an aqueous solution of $\mathrm{Ca}(\mathrm{OH})_2$. The excess unreacted $\mathrm{Ca}(\mathrm{OH})_2$ was later neutralized with 0.1 M of 40 mL HCl . If the volume of the sealed container of $\mathrm{CO}_2$ was $x$, then $x$ is ____________ $\mathrm{cm}^3$ (nearest integer). [Given : The entire amount of $\mathrm{CO}_2(\mathrm{~g})$ reacted with exactly half the initial amount of $\mathrm{Ca}(\mathrm{OH})_2$ present in the aqueous solution.]

Answer (integer) 45

Solution

<p>Let moles of $\mathrm{CO}_2=\mathrm{n}$ <br/><br/>moles of $\mathrm{Ca}(\mathrm{OH})_2$ <br/><br/>total initially $=2 \mathrm{n}$ <br/><br/>excess $\mathrm{Ca}(\mathrm{OH})_2=\mathrm{n}$ <br/><br/>gm equivalent of $\mathrm{Ca}(\mathrm{OH})_2=$ gm equivalent of HCl</p> <p>$$ \begin{aligned} & \mathrm{n} \times 2=0.1 \times \frac{40}{1000} \times 1 \\ & \mathrm{n}=2 \times 10^{-3} \end{aligned} $$</p> <p>Volume of $\mathrm{CO}_2=2 \times 10^{-3} \times 22400=44.8 \mathrm{~cm}^3$</p>

About this question

Subject: Chemistry · Chapter: Redox Reactions · Topic: Oxidation States

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