Chapter 15, Problem 18A

Interpretation Introduction

Interpretation:

Number of moles of NaOH per litre of solutionhave to be calculated.

Concept Introduction:

Composition of a solution can be defined by expressing its concentration. The concentrations of solutions can be expressed in different ways, which are involved in the quantity of solute and the quantity of solution or solvent. Various methods are used to described the concentration of the solution quantitatively. Some commonly used quantitative concentration terms are percent by mass, percent by volume, molarity, molality and mole fraction.

Molarity: Molarity is defined as the number of moles of solute present in one litre of the solution In expression, $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofthesolute}{Molecularweightofthesolute}$

Answer to Problem 18A

Number of moles of NaOH per litre of solutionis 0.105.

Explanation of Solution

  $\mathrm{Molarity}ofthesolution=\frac{Numberofmolesof the solute}{ Volume of the solution(inlitre)}$

Molarity of NaOH solution = 0.105 M.

  $\begin{array}{l}MolarityofNaOHsolution=\frac{Numberofmolesof NaOH}{ Volume of NaOH solution(inlitre)}\\ Numberofmolesof NaOH=MolarityofNaOHsolution\times Volume of NaOH solution(inlitre)\\ Numberofmolesof NaOH=0.105mol/litre\times 1litre=0.105mole\end{array}$