One litre of oxygen at NTP weighs 1.46 g. How many litres of oxygen are needed for the combustion of 21.0 g of Mg whose equivalent weight is 1/2 mole?

One litre of oxygen at NTP weighs 1.46 g. How many litres of oxygen ar

1.	One litre of oxygen at NTP weighs 1.46 g. How many litres of oxygen are needed for the combustion of 21.0 g of Mg whose equivalent weight is 1/2 mole?
Answer» SOLUTION :The volume occupied by 1 equivalent at NTP is equivalent volume. `therefore` equivalent volume of oxygen `=` volume of 8.0 g of oxygen at NTP (eq. WT. of O = 8 ) `= ( 8)/( 1.46) = 5.48` litres. (1.46) g oxygen contains 1 L at NTP) Given that the equivalent weight of `MG = (1)/(2)xx 24 = 12 ""`(wt. of 1 mole of Mg = 24 g) Now, in the COMBUSTION, equivalent of Mg = equivalent of oxygen. `therefore ("weight of Mg")/("eq. weight of Mg")=("volume of oxygen at NTP")/("eq. volume of oxygen")` `(21)/(12) = ("volume of oxygen")/(5.48)` `therefore` volume of oxygen `=` 9.59 litres.