Which condition is more favorable for the melting of ice?

Which of the following conditions is favourable for the production of ammonia by Haber's process?

The reaction $CaCO_3 \rightleftharpoons CaO + CO_{2(g)}$ goes to completion in a lime kiln because:

Based on Le Chatelier's principle,which of the following information is obtained?

Which among the following reactions is favoured in the forward direction by an increase in temperature?

When a vapor is heated slowly from $25\,^oC$ at atmospheric pressure,its color initially deepens. When the temperature is increased above $160\,^oC$,the color fades. At $600\,^oC$,the vapor becomes almost colorless,but when the pressure is increased at this temperature,the color deepens again. What is this vapor?