For A: Molar mass of H2O=18 g/mol. Moles of H2O=181.8×10−3=10−4. Since each H2O molecule has 3 atoms, the number of atoms = 3×10−4×NA.
For B: Molar mass of H2SO4=98 g/mol. Moles of H2SO4=989.8×10−3=10−4. Since each H2SO4 molecule has 7 atoms, the number of atoms = 7×10−4×NA.
For C: Molar mass of C=12 g/mol. Moles of C=121.8×10−3=1.5×10−4. The number of atoms = 1.5×10−4×NA.
For D: Molar mass of NaCl=58.5 g/mol. Moles of NaCl=58.55.85×10−3=10−4. Since each NaCl formula unit has 2 atoms, the number of atoms = 2×10−4×NA.
Thus, the correct matching is A-III, B-IV, C-II, D-I.
Answer: A-III, B-IV, C-II, D-I
Match List-I with List-II. List-I Mass of substance List-II Number of atoms A. 1.8 mg water I. 2× 10^-4× N_A B. 9.8 mg sulphuric acid II. 1.5× 10^-4×…
JEE Main 2026 — Chemistry Physical Chemistry
2026mcqmedium
Match List-I with List-II.
| List-I Mass of substance | List-II Number of atoms |
|---|---|
| A. 1.8 mg water | I. 2×10−4×NA |
| B. 9.8 mg sulphuric acid | II. 1.5×10−4×NA |
| C. 1.8 mg carbon | III. 3×10−4×NA |
| D. 5.85 mg salt (NaCl) | IV. 7×10−4×NA |
Official previous-year question
Held on 8 Apr 2026 · Verified 1 Jul 2026.
Options
- A
A-IV, B-III, C-I, D-II
- B
A-III, B-II, C-IV, D-I
- C
A-III, B-IV, C-II, D-I
- D
A-III, B-IV, C-I, D-II
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