Chemical Equilibrium is one of the common terms when it about Chemistry. This chapter holds a significant weightage of almost 4-5% and different styles of questions are asked in NEET. Like direct questions on reactions or sometimes questions required to be solved using formulas. Also Check NEET Chemistry Syllabus
Chemical Equilibrium is an important chapter in exams like NEET, etc. which can’t be ignored at all. Go through the detailed article which will provide you a detailed idea about chemical equilibrium.
Equilibrium is the state of a process where the properties such as temperature, pressure, and concentration among others of the system don’t show any change even with time. All the processes attaining equilibrium, two opposing processes are involved and Equilibrium is set to be achieved when the rates of the two opposing processes become the same.
Ques: When the system A + B C + D is at equilibrium, choose the correct option?
The correct option is E
Ques: 2SO3(g) 2SO2(g) + O2(g). The conventional equilibrium constant expression (Kc) for the system mentioned in the equation will be represented as:
[SO2]2/[SO3]
The correct option is B
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Reversible reaction: Reversible reactions are those reaction where not only the reactants react to form the products under different conditions but also the products also react to form reactants under the same conditions.
For instance: 3Fe(s) + 4H2O(g) Fe3O4(s) + 4H2(g).
Irreversible reaction: A reaction can’t take place in the reverse direction, which similar means that products formed don’t react to give back the reactants under the same condition.
Example: AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(g)
The formula representing a chemical equilibrium is A+bB cC+bD , where A, B are reactants while C and D are the products.
Important term | Explanation |
---|---|
Homogeneous equilibrium | All the reactants and products of any reaction in equilibrium ill have the same physical property. For instance: N2(g) + 3H2(g) 2NH3 (g) |
Heterogeneous equilibrium? : | Physical state of one or more of the reacting species can be different which mean that all the reactants and products might not have the same physical property. For instance 2NaHCO3(s) Na2CO3(s) + CO2(g) + H2O(l)? |
Ques: Consider the following reversible reaction. In a 3.00 liter container, some of the amounts that are found in equilibrium at 400 oC: 0.0420 mole N2, 0.516 mole H2 and 0.0357 mole NH3 would be. You need to calculate Kc. N2(g) + 3H2(g) 2NH3(g)
The correct option is B
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The law states that the rate at which a substance reacts would be directly proportional to its active mass; rate of a chemical reaction will be directly proportional to the product of active masses of reactants, where each will be increased to a power equal to the corresponding stoichiometric coefficient that appears in the balanced chemical equation.
Fore reaction aA+bBcC+bD
Rate of reaction ∝ [A]a.[B]b
or rate of reaction = K[A]a[B]b
Here K is the constant rate or velocity constant of the reaction at a particular temperature.
(Here n is order of reaction.)
For the unit concentration of reactants rate of the reaction will be equal to the rate constant or specific reaction rate.
Note: Active mass is defined as the molar concentration of the reacting substances that take part in the reaction.
Thus,
Active mass will be equal to the number of moles/volume in litres
Active mass of solid is taken as unity.
Also, Active mass of reactant (a) = Conc. × activity coefficient
i.e. a = Molarity × f for dilute solution f = 1
Applying Law of mass action for general reversible reaction would be aA + bB cC + dD
Rate of forward reaction ∝ [A]a[B]b
or Rf = Kf [A]b [B]b
Similarly for backward reaction
Rb = Kb[C]c [D]d
At equilibrium Kf[A]a[B]b = Kb[C]c[D]d
The above equation is known as the equilibrium equation and Kc is known as equilibrium constant. The equilibrium constant for the reverse reaction is the inverse of the equilibrium constant for the reaction in the forward direction.
Statement: When a chemical reaction at equilibrium is subjected to any stress, the equilibrium will get shifted in that direction where the stress effect is lower.
Name of acid | Properties |
---|---|
Arrhenius Definition | a. Acids give H+ ions aqueous solutions. b. Bases give OH- ions in aqueous solution. |
Bronsted – Lowry Definition | a. Acid is a proton donor . b. Base is a proton acceptor |
Strong and Weak Acids: | Strong acid dissociate completely in aqueous solution. |
Along with an ion to equilibrium, in case there are same ion it will make the equilibrium `reaction move in a direction to consume that ion.
This clearly indicate that water will dissociate lesser under the presence of HCl.
Buffer Solutions: Resists change in its pH when a change happens due to the addition of a small amount of acid or base is being referred to as buffer solution.
It is created by a combination of a weak acid and a salt of the acid with a strong base. For example, CH3COOH & CH3COONa pH = pKa + log [Conjugated base]/ [Acid]
For weak dibasic acid, pH = (pKa1 + pKa2 )/2
Here pKa1 and pKa2 are 1st and 2nd dissociation constant of the acid.
It is formed by combination of a weak base and a salt of the base with a strong acid. Example, NH4OH and NH4Cl pH = pKb + log [Conjugated acid]/ [Base]
Amount (moles) of the salt that has made the solution saturated per liter of solution is referred to as the solubility of the salt. For salt AB, AB ↔A+ +B-, Ksp = [A+][B-]
Solution that don’t have the product of the concentration of the ions more than KSP of the salt in solution.
Ques: The equilibrium is constant at 427oC for the reaction: N2(g) + 3H2(g) 2NH3(g) is Kp = 9.4 x 10-5. What will be the worth of Go in the reaction at 427o.
The correct option is C
Ques: For a particular reaction, which of the beneath statements can be made about K, the equilibrium will be constant?
The correct option is C
Ques: Let us consider that the equilibrium is constant for a reaction A + 2B C + 5/2 D which has a value of 4.0. Calculate the value of the equilibrium constant for the reaction 2C + 5D 2A + 4B if the temperature remains the same?
The correct option is B
Ques: What will be the pH of a solution when 0.01 M HCl and 0.1 M NaOH are mixed in equal volumes?
The correct option is A
Ques: From the following aqueous solutions which one is the best conductor of electricity?
The correct option is C
What will be relations between KC and KP for different types of reactions
Synthesis of ammonia (Haber's process)
*The article might have information for the previous academic years, please refer the official website of the exam.