1.

What is the mass of hydrogen peroxide present in 1 litre of a 2M solution? Calculate the volume of oxygen a N.T.P. liberated upon the complelte decomposition of 100mL of the solution.

Answer»

Solution :STEP-I CALCULATION of mass of `H_(2)O_(2)`
According to available data:
Molarity=`2M("or 2 mol"L^(-1))`, Molecular mass of `H_(2)O_(2)`=34g/mol, VOLUME of solution=1L
`"Molarity"=("Mass of"H_(2)O_(2))/(("Molecular mass of")` `H_(2)O_(2))/("Volume of solution oin litres")),("2mol"L^(-1))=("Mass of"H_(2)O_(2))/("34gmol"^(-1)xx(1L))`
OrMass of `H_(2)O_(2)=(2mol L^(-1)xx(34gmol^(-))xx(1L)=68g`
STEP-II Calculation of volume of oxygen liberated at N.T.P.
Now, 1000ML of the solution CONTAINS `H_(2)O_(2)=68g`
100mL of the solution contains `H_(2)O_(2)`=6.8g
Now, according to the DECOMPOSITION equation, `68.0g "of" H_(2)O_(2) "`at N.T.P. evolve oxygen"`=22400mL`
`68.0g "of" H_(2)O_(2) "at N.T.P. evolve oxygen"=(22400)/(68.0)xx6.8=22400or 2.24L`


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