The molecular mass of NaOH (Sodium Hydroxide) is 40 g/mol. It is calculated by adding the atomic masses of its constituent elements: Na (23) + O (16) + H (1) = 40 g/mol. NaOH is a strong base also known as caustic soda, widely used in industry and chemistry laboratories.
Molecular mass of NaOH = 40 g/mol.
Calculation: Na (23) + O (16) + H (1) = 40.
NaOH = Sodium Hydroxide; common name = Caustic Soda.
NaOH is a strong base — fully ionises in water.
1 mole NaOH = 40 g = 6.022 × 10²³ molecules.
Used in soap making, paper industry, water treatment.
Reaction with HCl: NaOH + HCl → NaCl + H₂O (neutralisation).
Chemical Formula: NaOH Chemical Name: Sodium Hydroxide (Common name: Caustic Soda)
Calculation of Molecular Mass: • Na (Sodium) — Atomic mass = 23 u • O (Oxygen) — Atomic mass = 16 u • H (Hydrogen) — Atomic mass = 1 u • Molecular mass of NaOH = 23 + 16 + 1 = 40 g/mol
Molecular Mass = 40 g/mol (or 40 u)
Physical Properties of NaOH: • Appearance: White solid (pellets, flakes, or granules) • Solubility: Highly soluble in water (exothermic dissolution) • Melting point: 318°C • Strong base (pH > 14 in solution)
Chemical Properties: • Strong alkali — fully dissociates in water: NaOH → Na⁺ + OH⁻ • Reacts with acids: NaOH + HCl → NaCl + H₂O (neutralisation) • Reacts with CO₂: 2NaOH + CO₂ → Na₂CO₃ + H₂O • Reacts with amphoteric metals: 2NaOH + 2Al + 2H₂O → 2NaAlO₂ + 3H₂↑
Uses of NaOH: • Paper and pulp industry • Soap and detergent making (saponification) • Drain cleaners (dissolves grease and hair clogs) • Water treatment • Chemical synthesis • Textile industry (mercerisation of cotton) • Food processing (curing olives, making pretzels)
Related Calculations: • 1 mole of NaOH = 40 g • 2 moles of NaOH = 80 g • Number of molecules in 40 g of NaOH = 6.022 × 10²³
Similar Molecular Masses for Comparison:
| Compound | Molecular Mass |
|---|---|
| NaOH | 40 g/mol |
| NaCl | 58.5 g/mol |
| KOH | 56 g/mol |
| Ca(OH)₂ | 74 g/mol |
| H₂SO₄ | 98 g/mol |
The molecular mass of NaOH (Sodium Hydroxide / Caustic Soda) is 40 g/mol. Calculation: Na (23) + O (16) + H (1) = 40 g/mol. NaOH is a strong base that fully dissociates in water. 1 mole of NaOH weighs 40 grams and contains 6.022 × 10²³ molecules.
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