Test: Chemical kinetics & The d & f block elements (December 15) - NEET MCQ

A catalyst affects equally both forward and backward reactions, therefore it does not affect equilibrium constant of reaction.

PbI₂ is yellow and is called golden spangles.

Given initial concentration (a) = 2.00 m; Time taken (t) = 200 min and final concentration (a – x)    = 0.15 m. For a first order reation rate constant,

Further

Cinnabar (HgS) is an ore of Hg.

The rate of a reaction is the speed at which the reactants are converted into products.
It depends upon the concentration of reactants. e.g for the reaction

∵ r = k[A]ⁿ
if n = 0
r = k[A]⁰ or  r = k thus for zero order reactions rate is equal to the rate constant.

Pm is obtained by synthetic method.

Hence ion is obtained.

We know that regular decrease in the size of the atoms and ions is called lanthanide contraction. In vertical column of transition elements there is a very small change in size and some times size is found same from second member to third member.The similarity in size of the atoms of Zr and Hf is evident due to the object of lanthanide contraction. Therefore Zr and Hf both have same radius 160 pm.

from the unit of rate constant it is clear that the reaction follow first order kinetics. Hence by rate law equation,    
 r = k [N₂O₅] where r = 1.02 × 10^–4,
k = 3.4 × 10^–5 1.02 × 10^–4 = 3.4 × 10^–5 [N₂O₅]
[N₂O₅] = 3M

From data 1 and 3, it is clear that keeping (B) const, When [A] is doubled, rate remains unaffected. Hence rate is independent of [A]. from 1 and 4, keeping [A] constant, when [B] is doubled, rate become 8 times. Hence [rate ∝ [ B]³].

Thus energy of activation for reverse reaction depend upon whether reaction is exothermic or endothermic If reaction is exothermic,  ΔH = +ve E_a(b) > E_a(f) If reaction is endothermic  ΔH =+ve E_a(b) < E_{a(f )}

When steel is heated in presence of NH₃ , iron nitride on the surface of steel is formed which imparts a hard coating. This process is called nitriding.

Given, 

when k₁ and k₂ are equal at any temperature T, we have

or 2.303 ×1×T=1000           [∴ log 10= 1]

We know that when nitrogen oxide (NO) combines with Fe (II) ions, a brown complex is formed. This reaction is called brown ring test