Q.Mention the conditions required to maximise the yield of ammonia.

Step 1 — Write the equilibrium and note its nature.

The forward reaction is exothermic and reduces the total moles of gas (4 mol reactant gas → 2 mol product gas).

Step 2 — Apply Le Chatelier's principle for each condition.

• Pressure: since the forward direction has fewer gas moles, increasing pressure shifts equilibrium forward → use high pressure (typically ~200 atm industrially).
• Temperature: being exothermic, low temperature favours the forward (product) direction, but too low a temperature makes the rate impractically slow → an intermediate/optimum temperature (~700 K, i.e. ~450 °C) is used as a compromise between yield and rate. …

Write the Haber equilibrium with its thermodynamic character (exothermic, mole-decreasing), then apply Le Chatelier's principle systematically to pressure and temperature, …

• Don't say "very low temperature" is used — very low temperature would favour yield thermodynamically but makes the reaction rate impractically slow, so an optimum/moderate temperature (~700 K) is the real industrial choice. …