Question

This is table 7.2


PLISSSSS ​

Answer 1

Average volume of H2SO4 used = (9.90 + 10 + 10.1) / 3

= 10 cm3

(subtract the final reading by inital reading and calculate the mean).

Write the balanced equation between the reaction of H2SO4 and KOH:

H2SO4 + 2KOH ---> K2SO4 + 2H2O

no. of moles of H2SO4 used = concentration x volume (in dm3)

= 1 x 10/1000

=0.01 mol

From the equation, the mole ratio of H2SO4 : KOH = 1:2,

meaning every 1 mole of H2SO4 reacts with 2 moles of KOH.

Hence, no. of moles of KOH required = 0.01 x 2 =0.02 mol

Molarity = no. of moles / volume (in dm3)

Therefore the molarity of KOH = 0.02 / (25/1000)

= 0.8M