Question

In the gaseous reaction of type, $aA+bB\to cC+dD$, which is wrong?
(A) a liters of A combines with b liters of B to give C and D
(B) a mol of A combines with b mol of B to give C and D
(C) a g of A combines with b g of B to give C and D
(D) a molecule of A combines with b molecule of B to give C and D

Answer 1

To solve this type of question we have to analyze each and every option i.e. by eliminating the options which are correct. A reaction is expressed in many ways in terms of number of moles, volume etc.

Complete solution:
Let’s check each of the following statements whether they are correct or incorrect.

The first statement is a liters of A combines with b liters of B to give C and D- this statement is true as from the given equation $aA+bB\to cC+dD$ we can say that a liters of A combine with b liters of B to given c liters of C and d liters of D.
The second statement is a mol of A combines with b mol of B to give C and D this statement is true as from the given equation $aA+bB\to cC+dD$ we can say that a mole of A combine with b mole of B to given c mole of C and d mole of D.
The third statement is a g of A combines with b g of B to give C and D this statement is incorrect as the correct statement will be a ${{M}_{A}}$ g of A combines with b ${{M}_{B}}$ g of B to give c ${{M}_{c}}$ g of C and d ${{M}_{D}}$ g or D. where M is the molar mass of A, B, C and D respectively.

Hence, the correct answer is option C.

Note: Stoichiometric calculation is done involving the gases to be converted between mass, number of moles and the volume of the gas. For example 1 mole of any gas at the standard temperature and pressure i.e. STP occupies a volume of 22.4L.