Pinku took two closed vessels for carrying out two different reversible reactions. The first reaction was the thermal decomposition of cupric nitrate and the second reaction was the synthesis of iodine pentafluoride from its constituents. After the reactions reached the state of equilibrium, he changed the pressure on both the reaction mixtures keeping the other parameters unaltered. In the first reaction vessel, he observed that the intensity of brown colour had been decreasing and in the other reaction vessel, the intensity of purple colour had been increasing. Explain the reason behind such observation.

Pinku took two closed vessels for carrying out two different reversibl

1.	Pinku took two closed vessels for carrying out two different reversible reactions. The first reaction was the thermal decomposition of cupric nitrate and the second reaction was the synthesis of iodine pentafluoride from its constituents. After the reactions reached the state of equilibrium, he changed the pressure on both the reaction mixtures keeping the other parameters unaltered. In the first reaction vessel, he observed that the intensity of brown colour had been decreasing and in the other reaction vessel, the intensity of purple colour had been increasing. Explain the reason behind such observation.
Answer» Solution :Decomposition of cupric nitrate `2Cu(NO_(3))_(2)hArr 2CuO+4NO_(2(g))+O_(2(g))` Brwon Synthesis of iodine pentafluoride, `I_(2(g))+5F_(2(g)) hArr 2IF_(5(g))` Purple Since the intensity of brown colour was decreasing in the first reaction, it can be concluded that the PRESSURE on the equilibrium mixture increased. Since the intensity of purple colour was increasing in the second reaction, it can concluded that the pressure on the equilibrium mixture decreased. According to LE Chatelier's principle, if the pressure increases, the reaction proceeds in a DIRECTION in which the number of moles decreases and vice versa.