THEORY:
Reaction HCl + NaOH——-> NaCl + H₂O
Ionically, H+ + OH– ————> H₂O
The normality strength of the alkali can be determined by titrating it against the standard acid, and by using the normality equation.
V₁N₁ = V₂N₂
Where, V₁ = volume of acid V₂ = volume of alkali
N₁ = normality of acid N₂ = normality of alkali
= N₂ =V₁N₁/V₂
APPARATUS :
1) Burette
2) Pipette
3) Conical flask
4) Burette stand
5) Clamps
CHEMICALS:
1) Methyl orange indicator
PROCEDURE :
Proceed exactly as in expt 2, and tabulate the results as follows
RESULTS:
Solution taken in the burette = HCl acid
Alkali taken for each titration = 10 ml
Indicator used = methyl orange
End point = from yellow to light pink
Normality of standard acid =N/10 (f = 1.10)
| No. of obs. | Initial reading | Final reading | Vol of acid (ml) | Means |
| 1 | 10.6 ——> | (approx) | ||
| 2 | 10.4 | |||
| 3 | 10.3 | 10.3 | ||
| 4 | 10.3 |
CALCULATIONS :
Acid Alkali
V₁ = 10.3 ml V₂ = 10 ml
N₁ = N/10 (f = 1.10) N₂ = ?
By applying the normality equation,
V₁N₁ = V₂N₂
10.3 ml x N/10 x 1.10 = 10 ml x N₂
N₂ = 10.3 × N × 1.10/10 × 10
=N/10 (f=1.133)