Tips & Tricks for Chemical Equilibrium
1. Pure ice can be made to melt at a temperature slightly below 0°C by increasing the pressure. As the water so obtained on melting is below 0°C, it refreezes when pressure is reduced. It is called regelation of ice.
2. Increase in external pressure always increases the boiling point and vice-versa.
3. If the reaction is multipled by 2, the equilibrium constant is squared.
4. When a bottle of coca or beer is opened, the pressure is decreased and dissolved CO2 gas escapes out with a fizze.
5. Increase in pressure favours melting of ice into water
6. Flash evaporation is a technique generally used for concentrating certain aqueous solutions which cannot be concentrated by normal boiling.
7. Freeze drying is a technique where water is made to sublime off at a temperature below 0°C.
Ordinary Thinking Objective Questions
Reversible and Irreversible reaction
1. A reversible reaction is one which
(a) Proceeds in one direction
(b) Proceeds in both directions
(c) Proceeds spontaneously
(d) All the statements are wrong
2. Which of the following is a characteristic of a reversible reaction
(a) Number of moles of reactants and products are equal
(b) It can be influenced by a catalyst
(c) It can never proceed to completion
(d) None of the above
3. The reaction CaCO3 ⇌ CaO+CO2(g) goes to completion in lime kiln because
(a) Of the high temperature
(b) CaO is more stable than CaCO3
(c) CaO is not dissociated
(d) CO2 escapes continuously
4. In the given reaction N2 + O2 ⇌ 2NO, equilibrium means that
(a) Concentration of reactants is changing where as concentration of products is constant
(b) Concentration of all substances is constant
(c) Concentration of reactants is constant where as concentration of products is changing
(d) Concentration of all substances is changing
5. Which of the following reactions is reversible
6. All reactions which have chemical disintegration
(a) Is reversible
(b) Is reversible and endothermic
(c) Is exothermic
(d) Is reversible or irreversible and endothermic or exothermic
7. Amongst the following chemical reactions the irreversible reaction is
(a) H2 + I2 ⇌ HI
(b) AgNO3 + NaCl ⇌ AgCl + NaNO3
(c) CaCO3 ⇌ CaO + CO2
(d) O2 + 2SO2 ⇌ 2SO3