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ChemistryNEET 2025Mole concept and molar mass

Some Basic Concepts of Chemistry

Among the following, choose the ones with an equal number of atoms.

A. 212 g of Na2CO3(s)\mathrm{Na_2CO_3(s)} [molar mass = 106 g]

B. 248 g of Na2O(s)\mathrm{Na_2O(s)} [molar mass = 62 g]

C. 240 g of NaOH(s) [molar mass = 40 g]

D. 12 g of H2(g)\mathrm{H_2(g)} [molar mass = 2 g]

E. 220 g of CO2(g)\mathrm{CO_2(g)} [molar mass = 44 g]

Choose the correct answer from the options given below:

  1. A.A, B and C only
  2. B.A, B and D only✓
  3. C.B, C and D only
  4. D.B, D and E only

Solution

Atoms == moles ×\times atoms per formula unit. A: 2×6=122 \times 6 = 12 mol atoms. B: 4×3=124 \times 3 = 12. C: 6×3=186 \times 3 = 18. D: 6×2=126 \times 2 = 12. E: 5×3=155 \times 3 = 15. A, B and D are equal.

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