Chapter 14.2, Problem 32SSC

Interpretation Introduction

Interpretation:

The similarity and difference between 1 molar that is 1M NaOH solution and 1 molar that is 1m NaOH solution is to be defined.

Concept introduction:

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

Again $\mathrm{Number}ofmolesofsolute=\frac{Massofsolute}{molecularweightofsolute}$

While molality is defined as defined as the number of moles of solute per kilogram of solvent.

Molality is denoted by ‘m’. The volume of a solution changes with temperature, this change in volume alters the molarity of the solution. Masses, however, do not change with temperature. Molality does not change with change of temperature.

In expression $\mathrm{Molality}ofsolution=\frac{Numberofmolesofsolute}{Molecularweightofsolute}$

Again, $\mathrm{Number}ofmolesofsolute=\frac{Massofsolute}{molecularweightofsolute}$

Answer to Problem 32SSC

Similarity:

Both the solutions contain NaOH that is solute dissolved in water that is solvent.

Difference: 1Msolution contains 1 mole of NaOH that is solute per liter of solution while 1msolution contains 1 moleof NaOH per kilogram of water.

Explanation:

1 M means, molarity of NaOH solution is equals to 1M, that is 1 mole of solute(NaOH) in 1 litre of water. As Molarity, is given by the equation:

$\mathrm{Molarity}ofsolution=\frac{Numberofmolesofsolute}{Volumeofsolution(inlitre)}$

So, 1 M = 1 mole of NaOH/1 litre solution(Water).

While 1m means, molality of NaOH, is equals to 1m, that is 1 mole of solute(NaOH) in 1 litre of water. As Molarity, is given by the equation:

In expression $\mathrm{Molality}ofsolution=\frac{Numberofmolesofsolute}{Molecularweightofsolute}$

So, 1m = 1 mole of NaOH/1 kg of solvent(Water).

Similarity -As it can be seen in both the equation, solute is NaOH and water is solvent. So, both the solutions contain NaOH that is solute dissolved in water that is solvent.

While the difference that can be seen from the equation is that, 1Msolution contains 1 mole of NaOH that is solute per litre of solution while 1msolution contains 1 mole of NaOH per kilogram of water.

Explanation of Solution

1 M means, molarity of NaOH solution is equals to 1M, that is 1 mole of solute(NaOH) in 1 litre of water. As Molarity, is given by the equation:

$\mathrm{Molarity}ofsolution=\frac{Numberofmolesofsolute}{Volumeofsolution(inlitre)}$

So, 1 M = 1 mole of NaOH/1 litre solution(Water).

While 1m means, molality of NaOH, is equals to 1m, that is 1 mole of solute(NaOH) in 1 litre of water. As Molarity, is given by the equation:

In expression $\mathrm{Molality}ofsolution=\frac{Numberofmolesofsolute}{Molecularweightofsolute}$

So, 1m = 1 mole of NaOH/1 kg of solvent(Water).

Similarity -As it can be seen in both the equation, solute is NaOH and water is solvent. So, both the solutions contain NaOH that is solute dissolved in water that is solvent.

While the difference that can be seen from the equation is that, 1Msolution contains 1 mole of NaOH that is solute per litre of solution while 1msolution contains 1 mole of NaOH per kilogram of water.