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Analysis of Sodium Hydroxide (NaOH)

Qualitative analysis

Aim

To analyse the given inorganic salt for one acidic and one basic radical.

Preliminary Test

  • Colour: White
  • Odour: Odourless
  • State: Crystalline solid
  • Solubility: Soluble in water

Test of Anion (OH⁻)

ExperimentObservationInference
Universal IndicatorSolution turns blue or purpleOH⁻ may be present
Confirmatory Test
Phenolphthalein Test
Add phenolphthalein indicator to salt solution
Solution turns pinkOH⁻ is confirmed

Test of Cation (Na⁺)

ExperimentObservationInference
Flame test in a clean non-luminous flameIntense yellow flameNa⁺ may be present
Confirmatory Test
Zinc Uranyl Acetate Test
Take a filtrate and add zinc uranyl acetate solution
Yellow crystalline precipitateNa⁺ is confirmed

Result

The given salt contains Na⁺ as the cation (basic radical) and OH⁻ as the anion (acidic radical). The salt is Sodium Hydroxide (NaOH).

Precautions

  1. Handle the chemicals with care.
  2. Don't use excess of chemicals.
  3. Keep the mouth of the test tube away from the face.