Question

Consider the reaction $2A\to 2B\text{, B}\to \text{2C, 3C}\to \text{4D}$. The number of moles of $D$ formed starting with $4$ moles of $A$ are,
A.$8$
B.$16$
C.$4$
D.$10.67$

Answer 1

Hint: A mole is defined as the amount of material containing exactly $6.022\times {10}^{23}$ particles, which may be electrons, atoms, molecules, or ions. Moreover, moles can also be defined as the amount of substance that contains the same number of entities i.e. atoms, molecules, ions, or other particles as the number of atoms present in $12$ grams of the carbon- $12$ isotope. According to the International System of Units Mole is a unit of measurement for the amount of a substance.

Complete answer:
According to the question:
$2A\to 2B$
i.e. $2$ moles of reactant A gives two moles of product B.
Now, let at time $t=0$ , then $4$ moles of reactant A will give zero moles of product B. Similarly, at time $t=t$ zero moles of reactant A will give $4$ moles of product B. So in the end, $4$ moles of B is formed.
$B\to 2C$
Here, one mole of reactant B gives $2$ moles of product C.
Again, at time $t=0$ , $4$ moles of reactant B will give zero moles of product C. And, at time $t=t$ , zero moles of reactant B will give $8$ moles of product C. Hence, in the end, $8$ moles of product C is formed.
$3C\to 4D$
i.e. $3$ moles of reactant C gives $4$ moles of product D.
Now, $1$ mole of reactant C gives ${\displaystyle \frac{4}{3}}$ moles of product.
And, $8$ moles of reactant C will give ${\displaystyle \frac{4}{3}}\times 8=10.67moles$ of product D.

So, the correct answer is “Option D”.

Note:
The molar mass of a compound is defined as the given mass of the substance divided by the amount of the substance in that compound. Hence, it is the mass of one mole of the substance or $6.022\times {10}^{23}$ particles, expressed in grams. Molar mass is a bulk property not the molecular property of a substance.