JEE MAIN - Chemistry (2020 - 3rd September Evening Slot - No. 16)
The strengths of 5.6 volume hydrogen peroxide
(of density 1 g/mL) in terms of mass percentage
and molarity (M), respectively, are:
(Take molar mass of hydrogen peroxide as
34 g/mol)
0.85 and 0.5
0.85 and 0.25
1.7 and 0.25
1.7 and 0.5
Explanation
Volume strength = 11.2 × molarity
$$ \Rightarrow $$ molarity = $${{5.6} \over {11.2}}$$ = 0.5
Assuming 1 litre solution,
mass of solution = 1000 ml × 1 g/ml = 1000 g
mass of solute = moles × molar mass
= 0.5 mol × 34 g/mol
= 17 gm.
$$ \therefore $$ mass % =
= $${{17} \over {1000}} \times 100$$ = 1.7 %
$$ \Rightarrow $$ molarity = $${{5.6} \over {11.2}}$$ = 0.5
Assuming 1 litre solution,
mass of solution = 1000 ml × 1 g/ml = 1000 g
mass of solute = moles × molar mass
= 0.5 mol × 34 g/mol
= 17 gm.
$$ \therefore $$ mass % =
mass of solute
mass of solution
$$ \times $$ 100
= $${{17} \over {1000}} \times 100$$ = 1.7 %
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