reactions group 2 and group 7

reaction with water

metals react with water to form a metal hydroxide and hydrogen gas

M + 2H₂O → M(OH)₂ + H₂

solubility of metal hydroxides

increase down the group

solubility of metal sulphates

decreases down the group

extraction of titanium

1. TiO₂ converted to TiCl₄ by heating it with carbon in a stream of chlorine gas

2. purification via fractional distillation

3. reduction by magnesium at 1000°C

   TiCl₄ + Mg₂ → 2MgCl + Ti

removal of SO2 from flu gas

1. CaO + 2H₂O + SO₂ → CaSO₃ + 2H₂O

2. CaCO3 +2H₂O + SO₂ → CaSO₃ + 2H₂O + CO₂

making bleach

2NaOH + Cl₂ → NaClO +NaCl + H₂O

reaction of chlorine in water

H₂O + Cl₂ ←→ Cl^- + ClO^- + 2H⁺

decomposition of chlorine and water in sunlight

H₂O + Cl₂ ←→ 2Cl^- + 1/2 O₂ + 2H⁺

Sodium halide reaction with H₂SO₄

NaX + H₂SO₄ → HX +NaHSO₄

reduction of HX

Cl and F cant be reduced

2HX + H₂SO₄ → 2H₂O + X₂ + SO₂