Chemistry · Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry

JEE Main 2026 — 23 January, Morning Shift — Question 68

x mgx\,\mathrm{mg} of pure HCl\mathrm{HCl} was used to make an aqueous solution. 25.0 mL25.0\,\mathrm{mL} of 0.1 M0.1\,\mathrm{M} Ba(OH)2\mathrm{Ba(OH)_2} solution is used when the HCl\mathrm{HCl} solution was titrated against it. The numerical value of xx is ____×10−1\_\_\_\_ \times 10^{-1} (nearest integer).

(Given: molar mass of HCl=36.5\mathrm{HCl}=36.5 and Ba(OH)2=171.0 g mol−1\mathrm{Ba(OH)_2}=171.0\,\mathrm{g\,mol^{-1}})

Answer: 1825

Numerical answer — enter this value.

Step-by-step solution

Balanced reaction: Ba(OH)2+2HCl→BaCl2+2H2O\mathrm{Ba(OH)_2 + 2HCl \rightarrow BaCl_2 + 2H_2O}

Moles of Ba(OH)2\mathrm{Ba(OH)_2} =0.1×25.01000=0.0025 mol= 0.1 \times \frac{25.0}{1000} = 0.0025\,\mathrm{mol}

From stoichiometry, 1 Ba(OH)2→2 HCl1\,\mathrm{Ba(OH)_2} \rightarrow 2\,\mathrm{HCl}

Moles of HCl\mathrm{HCl} required =2×0.0025=0.005 mol= 2 \times 0.0025 = 0.005\,\mathrm{mol}

Mass of HCl\mathrm{HCl} =0.005×36.5=0.1825 g= 0.005 \times 36.5 = 0.1825\,\mathrm{g} =182.5 mg = 182.5\,\mathrm{mg}

Thus, x=182.5=1825×10−1x = 182.5 = 1825 \times 10^{-1}

Nearest integer = 18251825

Answer key and solution verified before publishing.

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Exam
JEE Main 2026
Subject
Chemistry
Chapter
Some Basic Concepts of Chemistry (Mole Concept) + Stoichiometry
Topic
Chemical Equations, Stoichiometry and Limiting Reagent