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How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves ...

How many grams of hydrogen gas will be liberated when 6g of magnesium ribbon dissolves in 500cm3 of 6M HCl?
(Mg=24, H=1, Cl=35.5)
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  • A 1.2 g
  • B 0.7 g
  • C 0.5 g
  • D 0.3 g
  • E 0.12 g
Correct Answer: Option C
Explanation:
Mg + 2HCl → MgCl2 + H2
6 molar contains 6 Χ 36.5 gms 1000 cc
Solution i.e 6 Χ 36.5/2gms in 500 cc
= 3 Χ 36.5
24 gms of mg will react with 2 Χ 36.5 HCl to liberate 2 gm of hydrogen
∴ 6 gms will liberate 6 Χ 2/24 Χ 1 = 0.5 gm of H2

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