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5 moles of AB 2 weigh 125 × 10 –5 kg and 10 moles of A 2 B 2 weigh 300 × 10 –3 kg. The molar mass of A (M A ) and molar mass of B (M B ) in kg mol are:

1. M A = 10 × 10 –3 and M B = 5 × 10 –3
2. M A = 25 × 10 –3 and M B = 50 × 10 –3
3. M A = 5 × 10 –3 and M B = 10 × 10 –3
4. M A = 50 × 10 –3 and M B = 25 × 10 –3

Correct answer: M A = 5 × 10 –3 and M B = 10 × 10 –3

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