Equilibrium

A catalyst increases the rate of the chemical reaction by making ____.

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A catalyst increases the rate of the chemical reaction by making new low energy pathway. Generally, all the reactions will follow a pathway where there are low energy needs. That low energy is called threshold energy. It is defined as the minimum energy required to convert the reactant into product. The presence of catalyst further lowers that energy, making the reaction move faster.

The greater the numerical value of equilibrium constant, ____ .

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The greater the numerical value of equilibrium constant, higher is the concentration of products. If the value is around zero or negative, then the concentration of product is very less.

A salt 'X' is dissolved in water of pH = 7. The salt is made resulting solution becomes alkaline in nature. The salt is made

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A salt of strong base with weak acid undergoes anionic hydrolysis to give basic solution.

When a liquid evaporates in a closed container, molecules with ____ energy will escape from liquid phase to vapor phase.

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When a liquid evaporates in a closed container, molecules with higher kinetic energy will escape from liquid phase to vapor phase. Vapor phase is a higher energy state. Hence, those molecules having higher kinetic energy can excite and go to higher energy vapor phase. This can happen in a closed container.

When HCI gas is passed through a saturated solution of NaCl, the solubility of NaCl

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The presence of common ion causes the solubility to decrease.

Equilibrium constant ‘K’ is directly related to ____.

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Equilibrium constant ‘k’ is directly related to Gibbs free energy. If ΔG is zero, then the reaction is in equilibrium state. If ΔG is negative , the reaction proceeds in the forward direction.

Equilibrium can be shifted forward by ____.

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Equilibrium can be shifted forward by removing the products. If we remove a portion of the product from the reaction mixture, equilibrium will be disturbed and shifts forward to maintain the equilibrium again. If we remove the reactants gradually or completely, the equilibrium shifts backward. Adding catalyst to the equilibrium will have no effect.

____ is the weak acid among the following acids.

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Nitrous acid is the weak acid among all the acids. Weak acid will not undergo complete dissociation in water. The other three acids are strong acids which undergo complete dissociation in water. Other examples for weak acid are acetic acid, HF etc.

Which of the following is not a general characteristic of equilibria involving physical processes?

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Without hint.

In dynamic equilibrium, the concentration of ____ will not change.

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In dynamic equilibrium, the concentration of products or reactants will not change. The rates of forward and reverse reactions become equal in dynamic equilibrium. Hence, at equilibrium condition, there is no change in the concentration of reactants or products.

During the process of salvation of ions, energy is ____.

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During the process of solvation of ions, energy is released. The solvation enthalpy of ions is always negative. This means that energy is released in the process of solvation.

The term ‘forward reaction’ refers to ____.

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The term ‘forward reaction’ refers to the reaction that converts products into reactants. Forward reaction means converting reactants into products and reverse reaction means converting products into reactants.

___ concept of acids and bases is followed to calculate the pH of weak electrolytes.

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Bronsted-Lowry concept of acids and bases is followed to calculate the pH of weak electrolytes. Weak acids and bases are commonly called as weak electrolytes. According to that theory, proton donors are called as acids and proton acceptors are called as bases.

Salts that ____ will be easily soluble in water.

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Salts that are hygroscopic will be easily soluble in water. Hygroscopic means having the ability to absorb water from the environment, when exposed to atmosphere. So, those salts that are hygroscopic in nature, will easily dissolve in water. Hence, these salts need more care during storage and transport.

The two opposing processes in liquid-vapour physical equilibrium are ____.

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The two opposing processes in physical equilibrium are evaporation and condensation. In liquid-vapor equilibrium, two opposing reactions always take place viz., evaporation and condensation. Both oppose each other, so that these two processes remain in physical equilibrium.

Which one of the following information can be obtained on the basis of Le Chatelier principle?

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According to Le-chatelier's principle" whenever a constraint is applied to a system in equilibrium, the system tends to readjust so as to nullify the effect of the constraint.

The addition of ____ to the equilibrium mixture leaves the equilibrium unaffected.

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The addition of argon gas to the equilibrium mixture leaves the equilibrium unaffected. Argon gas is an inert gas. It does not react with any of the chemicals in the reaction mixture. Hence, addition of argon gas (any inert gas) will not affect the equilibrium.

Suitable conditions for melting of ice:

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Melting of ice involve absorption of heat i.e Endothermic hence high temperature favour the process. Further for a given mass volume of water is less than ice thus high pressure favour the high temperature convert ice into liquid.

For the buffer solution (mixture of ammonium hydroxide and ammonium chloride) , ____ pH value can be maintained in the aqueous solutions.

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For the buffer solution (mixture of ammonium hydroxide and ammonium chloride) , 9.2 pH value can be maintained in the aqueous solutions. Since it is prepared from weak base and its salt, this buffer can be used to maintain alkaline pH values in the aqueous solutions.

For a positive value of ΔG, the reaction is ____.

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For a positive value of ΔG, the reaction is non-spontaneous. It won’t proceed (not feasible). This means that the particular combination of reactants will not produce the products. Alternatively, if ΔG is negative, the reaction proceeds in the forward direction.

Among the following acids _________ has more acid strength.

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HI has more acid strength. In the periodic table, all the halogens F, Cl, Br and I are placed vertically in the same group. From F to I, atomic number also increases and thereby size of the halogen atom also increases. H-I bond strength is less compared to H-F bond strength, as the size of the I is bigger. So, removing proton from HI is easier than from HF. Hence, bond strength is more for HI. The order of bond strength is HI > HBr > HCl > HF.

A catalyst ____ in a reaction.

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A catalyst does not have any impact on equilibrium in a reaction. Normally, a catalyst has no role on equilibrium. A catalyst does not alter the equilibrium, instead it reduces the duration of the reaction by making low energy pathway for the reactant.

A salt is formed from the combination of _____.

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A salt is formed from the combination of an acid and a base. For e.g., sodium chloride (NaCl) is formed from the reaction of acid (HCl) and base (NaOH).

Equilibrium constant depends on the ____ of the given reaction.

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Equilibrium constant depends on the temperature of the given reaction. Temperature alters the equilibrium concentration of the reactants and products. If temperature increases, equilibrium shifts towards forward reaction and vice-versa. So, equilibrium constant depends mainly on the temperature of the given reaction.

Equilibrium equation is also known as ____.

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The equilibrium equation is also known as law of mass action. In the earlier days, concentration was called as active mass. So, equilibrium equation is also known as law of mass action.

____principle is followed in common ion effect.

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Le Chatelier’s principle is followed in common ion effect. Shift in equilibrium is considered only in Le Chatelier’s principle. Aufbau principle, Heisenberg principle and Hund’s rule give idea about the filling of electrons in the orbitals of any atom.

The main goal of chemical synthesis is ____.

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The main goal of chemical synthesis is getting maximum conversion of reactants to products. In any chemical reaction, the main aim is to get maximum yield (conversion of reactants to products). Even though impurity forms or backward reaction take place, the aim will be achieved by proposing suitable conditions.

Based on Le Chatelier’s principle, for heterogeneous equilibrium reactions, the effect of pressure changes on ____ is ignored.

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Based on Le Chatelier’s principle, for heterogeneous equilibrium reactions, the effect of pressure changes on solid and liquid is ignored. The term 'concentration' is not used for solids and the concentration of liquid/solution is nearly independent of pressure. The concentration of only gaseous products are affected by pressure.

If the volume of the reaction mixture is halved, the partial pressure ____.

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If the volume of the reaction mixture is halved, the partial pressure is doubled. Generally, for low volume of liquid, pressure will be high and vice-versa. If the volume of the reaction mixture is halved, when compared with the original concentration, the partial pressure and concentration of the reaction mixture will be doubled.

Class 11th Chemistry - 7 Equilibrium MCQs
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