Chapter 15, Problem 7STP

Interpretation Introduction

Interpretation:

The solute with highest molarity is to be chosen.

Concept introduction:

Molarity is number of moles of solute present per liter of solution.

And number of moles is calculated by dividing given mass by molar mass.

Thus if mass of solute and volume of solution are taken same, then solution with lowest molar mass will have highest concentration.

Answer to Problem 7STP

D

Explanation of Solution

Molar mass of $NaOH$ = $23+16+1$

= $40g/mol$

Molar mass of $KCl$ = $39+35.5$

= $74.5g/mol$

Molar mass of $KOH$ = $39+16+1$

= $56g/mol$

Molar mass of $LiOH$ = $9+16+1$

= $26g/mol$

  $LiOH$ has lowest molar mass among all, so, it will have highest molarity.

Conclusion

Calculations show that option D is correct and remaining options are wrong.