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प्रश्न
Write two factors that affect the rate of reaction.
List the factors affecting the rate of reaction.
Explain briefly the various factors which affect the rate of a reaction.
On what factors does the rate of a reaction depend?
List any two factors that influence the rate of chemical reaction. Indicate whether the rate constant of the reaction is dependent on or independent of these factors.
Mention any two factors that influence the rate of a chemical reaction.
Mention the factors that affect the rate of a chemical reaction.
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उत्तर
- Nature of reactants: The makeup of the reactants affects how quickly a chemical reaction proceeds. For instance, reactions involving polar and ionic chemicals proceed fairly quickly, while those involving covalent compounds proceed considerably more slowly. Because the electrostatic interactions in their molecules are readily disrupted in aqueous solutions, reactions involving polar or ionic compounds proceed relatively quickly. Old bonds are broken and new bonds are formed, or the bonds are rearranged, in a chemical reaction involving covalent reactants. As a result, the rate of a reaction involving the rearrangement of bonds is determined by how easily the particular bonds are made or broken. For example, nitric oxide oxidises to nitrogen peroxide far more quickly than carbon monoxide oxidises to carbon dioxide. The two responses seem to be comparable.
\[\ce{2NO_{(g)} + O2_{(g)} -> 2NO2_{(g)} (fast)}\]
\[\ce{2CO_{(g)} + O2 -> 2CO2_{(g)} (slow)}\]
Because of variations in the energies required for the reactants' bond rearrangement, these two reactions have different speeds. - Concentration of reactants: In general, a reaction's rate rises as the reactant concentration does. Molecular collisions are more likely to occur when a reactant's concentration rises. As a result, the reaction rate rises.
- Temperature: Reaction rates typically rise with temperature. For most homogeneous reactions, increasing the temperature by 10° doubles or triples the rate. Temperature significantly affects reaction rates.
- Surface area: Solid reactants have a higher rate of reaction as their surface area increases. Finely split solid reactants have a higher surface area than huge reactants and react faster. For instance, powdered coal burns faster than lump coal.
Increasing the surface area of a solid reactant improves the contact area between two reactants. This increases the pace of molecular interactions, leading to faster reactions. - Presence of a catalyst: A catalyst is a material that speeds up a reaction while maintaining its amount and chemical makeup.
A catalyst accelerates the rate of a reaction. This is because it offers a less energy-intensive alternate path. Lowering the energy barrier allows more molecules of reactants to cross it. As a result, the rate of reaction rises.
The rate constant depends on the nature of the reactants, temperature, and catalyst, and it is independent of concentration and surface area.
Notes
Students should refer to the answer according to their question.
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संबंधित प्रश्न
A reaction is second order in A and first order in B.
(i) Write the differential rate equation.
(ii) How is the rate affected on increasing the concentration of A three times?
(iii) How is the rate affected when the concentrations of both A and B are doubled?
For a reaction : 
(i) Write the order and molecularity of this reaction.
(ii) Write the unit of k.
For the reaction:
\[\ce{2A + B -> A2B}\]
the rate = k[A][B]2 with k = 2.0 × 10−6 mol−2 L2 s−1. Calculate the initial rate of the reaction when [A] = 0.1 mol L−1, [B] = 0.2 mol L−1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L−1.
A reaction is second order with respect to a reactant. How is the rate of reaction affected if the concentration of the reactant is doubled?
For a reaction R ---> P, half-life (t1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction?
Consider a first order gas phase decomposition reaction given below :
\[\ce{A(g) -> B(g) + C(g)}\]
The initial pressure of the system before decomposition of A was pi. After lapse of time ‘t’, total pressure of the system increased by x units and became ‘pt’ The rate constant k for the reaction is given as ______.
Why does the rate of any reaction generally decreases during the course of the reaction?
Assertion: Order of the reaction can be zero or fractional.
Reason: We cannot determine order from balanced chemical equation.
Assertion: Order and molecularity are same.
Reason: Order is determined experimentally and molecularity is the sum of the stoichiometric coefficient of rate determining elementary step.
For a first order A → B, the reaction rate at reactant concentration of 0.01 m is found to be 2.0 × 10–5. The half-life period of reaction.
