Questions in chemical-aritmatic

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	$12g$of $Mg$(at.mass 24) on reacting completely with acid gives hydrogen gas, the volume of which at STP would be
	Which of the following has least mass
	How many mole of helium gas occupy $22.4\;L$ at ${0^o}C$ at 1 atm. pressure
	Volume of a gas at STP is $1.12 \times {10^{ - 7}}$cc. Calculate the number of molecules in it
	$4.4\;g$ of an unknown gas occupies $2.24L$ of volume at standard temperature and pressure. The gas may be
	The number of moles of oxygen in $1\;L$ of air containing 21% oxygen by volume, in standard conditions, is
	The number of molecules in $8.96\;L$ of a gas at ${0^o}C$ and 1 atmosphere pressure is approximately
	The equivalent weight of a metal is 9 and vapour density of its chloride is 59.25. The atomic weight of metal is
	The molecular weight of a gas is 45. Its density at STP is
	Equivalent weight of a bivalent metal is 37.2. The molecular weight of its chloride is