Question

The reaction of sulfuric acid (H2SO4) with potassium hydroxide (KOH) is described by the equation below. Suppose 0.06 L of KOH with unknown concentration is placed in a flask with bromothymol blue indicator. A solution of 0.20 M H2SO4 is dripped into the KOH solution. After exactly 0.017 L of H2SO4 is added, the indicator changes from blue to yellow. What is the concentration of the KOH

Answer 1

The concentration of the KOH is 0.056 M.

Step-by-step explanation:

The analytical method of titration is performed between KOH and H2SO4 in which bromothymol blue is a pH indicator used to detect the neutral point in a titration.

The formula used in the titration is:

Macid x V acid = Mbase x V base

The volume is in litre.

Data given:

volume of the base KOH = 0.06 Litre

molarity of the base KOH = ?

volume of the acid = 0.017 L

Molarity of the acid H2SO4 = 0.20M

Applying the formula and putting the values:

0.20 x 0.017 = Mbase x 0.06

M base = 0.20 x 0.017 ÷ 0.06

= 0.056 M

0.017 litre of 0.20 M acid is added against the 0.06 litres of KOH having molarity of 0.056 M.