Question

Which of the following quantities is equivalent to $18$ $\left( w/V \right)$ solution of urea (Molar mass$=60$ ).
A. $1\,M$
B. $2\,M$
C. $0.3\,M$
D. $3\,M$

Answer 1

The concentration of a solute is significant in examining chemical reactions since it decides how regularly molecules collide in solution and thus indirectly determines the rates of reactions and the conditions at equilibrium. Concentration might be expressed in various ways.

Complete answer:
Mass concentration of solution is communicated as $$ for weight per volume. It can then again be abbreviated to $w/V$ for mass per volume. This is utilized when a solid chemical is dissolved in a liquid.
Molarity (M) is the amount of a substance in a specific volume of solution. Molarity is characterized as the moles of a solute for every liter of a solution. Molarity is otherwise called the molar concentration of a solution.
Molecular weight of Urea or grams. The molecular formula for Urea is $C{{H}_{4}}{{N}_{2}}O$ .The SI base unit for amount of substance is the mole. $1\,mole$ is equivalent to $1\,mole$ Urea, or $60\,g$ .
Given:
$\%$ of Urea $=18$
$18\%$ of Urea $=\dfrac{18}{100}$
Which means $18\,gm$ of urea in $100\,mL$ of solution,
Let’s find out its molarity with help of formula,
Molarity $=\dfrac{No.of moles}{Volume}$
Number of moles $=\dfrac{mass}{Mola\,rmass}=\dfrac{18}{60}=0.3\,moles$ ……………………… (since molar mass$=60$ )
Solution in $L=\dfrac{100}{1000}$ $=0.1\,L$
Molarity $=\dfrac{0.3\,moles}{0.1\,L}=3\,M$

**Hence, the correct option is $3\,M$

Additional Information: **
Quantitative units of concentration incorporate molarity, molality, mass rate, parts per thousand, parts per million, and parts per billion.

Note:
Urea (otherwise called carbamide) is a waste product of many living life forms, and is the significant natural part of human urine. This is due to the fact that it is the end of a chain of reactions which separate the amino acids that make up proteins.