<u>Answer:</u> The mass of solid NaOH required is 80 g
<u>Explanation:</u>
Equivalent weight is calculated by dividing the molecular weight by n factor. The equation used is:

where,
n = acidity for bases = 1 (For NaOH)
Molar mass of NaOH = 40 g/mol
Putting values in above equation, we get:

Normality is defined as the umber of gram equivalents dissolved per liter of the solution.
Mathematically,

Or,
......(1)
We are given:
Given mass of NaOH = ?
Equivalent mass of NaOH = 40 g/eq
Volume of solution = 400 mL
Normality of solution = 5 eq/L
Putting values in equation 1, we get:

Hence, the mass of solid NaOH required is 80 g
The new volume of the bag will be 789.5 mL.
<u>Explanation:</u>
As per the Charles law, at constant pressure the volume of the gas is directly related to its temperature in Kelvin (K). That is as the temperature increases, the gas expands and vice-versa.

V1 = 250 ml
V2 = ?
T1 = 19° C
T2 = 60° C
Now we have to rewrite the equation to get the new volume as,
V2 = 
=
<em> </em>= 789.47 ≈ 789.5 ml.
So the new volume of the bag will be 789.5 mL.