Assertion: As mole is the basic chemical unit, the concentration of the dissolved solute is usually specified in terms of number of moles of solute.
Reason: The total number of molecules of reactants involved ina balanced chemical equation is known as molecularity of the reaction.

Options

A. (a)If both assertion and reason are true and the reason is the correct explanation of the assertion.
B. (b)If both assertion and reason are true and the reason is not the correct explanation of the assertion.
C. (c )If the assertion is true but reason is false.
D. (d)If assertion is false but reason is true.

Answer

b

Explanation

The number of moles of a solute present in one litre of solution is known is as molarity (M).
The total number of molecules of reactants present in a balenced chemical equation is known as molecularity. For example,
`PCl_(5) rarr PCl_(3)+Cl_(2)` (Unimilecular)
`2HCl rarr H_(2)+I_(2)` (Bimolecular)
`:.` Molarity and molecularity are used in different sense.