8.7 g of pure MnO2 is heated with an excess of HCI and the gas evolved is passed into a solution of KI. Calculate the amount of the iodine liberated (Mn = 55, Cl = 35.5, I =127):
A
0.1 mol
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B
25.4 g
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C
15.4 g
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D
7.7 g
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Solution
The correct option is A 25.4 g we have,
MnO2+HCl→Cl2+MnCl2+H2O
and 2KI+Cl2→KCl+I2
molecular weight of MnO2 = 87 g
no. of moles of MnO2 = 0.1 mole
so, from ist equation we have 1 mole of MnO2produce 1 mole of Cl2 and from 2nd equation 1 mole of Cl2 is producing;
so, 0.1 mole of MnO2 produces 0.1 mole of I2
amount of I2 produces = moles * molecular mass = 0.1 * 254 = 25.4 g