The equilibrium $2SO_{2(g)} + O_{2(g)} \rightleftharpoons 2SO_{3(g)}$ shifts forward,if

For the reaction $aA + bB \rightleftharpoons cC + dD$,if the equilibrium shifts in the backward direction at low pressure and high temperature,which of the following is correct?

Which condition is more favorable for the melting of ice?

For the reaction $CO_{(g)} + H_2O_{(g)} \rightleftharpoons CO_{2(g)} + H_{2(g)}$,the equilibrium amount of $CO_{2(g)}$ increases by:

Consider the equilibrium $CO_{(g)} + 3H_{2(g)} \rightleftharpoons CH_{4(g)} + H_2O_{(g)}$. If the pressure applied over the system increases by two-fold at constant temperature,then which of the following statements are correct?
$(A)$ Concentration of reactants and products increases.
$(B)$ Equilibrium will shift in the forward direction.
$(C)$ Equilibrium constant increases since the concentration of products increases.
$(D)$ Equilibrium constant remains unchanged as the concentration of reactants and products remain the same.
Choose the correct answer from the options given below:

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?