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

JEE Main 2026 — 8 April, Evening Shift — Question 43

Match List-I with List-II.

List-IMass of substanceList-IINumber of atomsA.1.8 mg waterI.2×10−4×NAB.9.8 mg sulphuric acidII.1.5×10−4×NAC.1.8 mg carbonIII.3×10−4×NAD.5.85 mg salt (NaCl)IV.7×10−4×NA\begin{array}{|c|l|c|l|} \hline \text{List-I} & \text{Mass of substance} & \text{List-II} & \text{Number of atoms} \\ \hline \text{A.} & 1.8\ \text{mg water} & \text{I.} & 2 \times 10^{-4} \times N_A \\ \hline \text{B.} & 9.8\ \text{mg sulphuric acid} & \text{II.} & 1.5 \times 10^{-4} \times N_A \\ \hline \text{C.} & 1.8\ \text{mg carbon} & \text{III.} & 3 \times 10^{-4} \times N_A \\ \hline \text{D.} & 5.85\ \text{mg salt }(\ce{NaCl}) & \text{IV.} & 7 \times 10^{-4} \times N_A \\ \hline \end{array}

Choose the correct answer from the options given below :

  1. Option A:

    A-IV, B-III, C-I, D-II

  2. Option B:

    A-III, B-II, C-IV, D-I

  3. Option C:

    A-III, B-IV, C-II, D-I

    Correct
  4. Option D:

    A-III, B-IV, C-I, D-II

Answer: C

Step-by-step solution

(A) No. of atoms in 1.8 mg1.8\,\mathrm{mg} water =1.8×10−318×NA×3=3×10−4NA=\frac{1.8\times10^{-3}}{18}\times N_{\mathrm{A}}\times3 =3\times10^{-4}N_{\mathrm{A}}

(B) No. of atoms in 9.8 mg H2SO49.8\,\mathrm{mg}\,\mathrm{H_2SO_4}

(C) No. of atoms in 1.8 mg1.8\,\mathrm{mg} carbon

(D) No. of atoms in 5.85 mg NaCl5.85\,\mathrm{mg}\,\mathrm{NaCl} =5.85×10−358.5×NA×2=2×10−4NA=\frac{5.85\times10^{-3}}{58.5}\times N_{\mathrm{A}}\times2 =2\times10^{-4}N_{\mathrm{A}}

Correct match: A−III, B−IV, C−II, D−IA-\mathrm{III},\ B-\mathrm{IV},\ C-\mathrm{II},\ D-\mathrm{I}

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
Introduction to Mole Concept
Match List-I with List-II. begin array c l c l hline List-I & Mass of… | JEE Main 2026 PYQ with Solution · DhiX AI