In a neutralization reaction involving HCI and NaOH using litmus as indicator, the colour at the end point is

1. Analyze the question You are titrating a strong acid (HCl) against a strong base (NaOH) with litmus as the indicator. The question asks for the colour at the end point, where the acid and base have exactly neutralised each other.

2. Concept

• Litmus is red in acid and blue in alkali (base).
• At the end point, the solution is neutral (pH ≈ 7), because HCl + NaOH gives NaCl (a neutral salt) and water.
• Litmus does not show a pure red or pure blue at neutrality. It shows an in-between colour, purple.

3. Solution

HCl + NaOH → NaCl + H₂O

• Before the end point (excess acid): litmus is red.
• After the end point (excess base): litmus is blue.
• At the end point (pH 7): litmus is purple, the mix of red and blue.

4. Answer The colour at the end point is purple.

5. Exam tip Remember this order: Red → Purple → Blue as you go from acid to neutral to base. Litmus is a poor indicator for sharp titration end points, but in JAMB questions "neutral" with litmus is always purple. Also, don't pick orange: that is associated with methyl orange in a weakly acidic to neutral transition, not with litmus.