ECAT Pre Engineering Chemistry Chapter 11 MCQ Test With Answer

Rate law of an equation is obtained :

• From a balance equation. A
• Can be calculated theoretically as well as determined experimentally. B
• It is only calculated theoretically. C
• Experimentally. D

It is common observation that rates of chemical reactions differ :

• Greatly. A
• A little bit. B
• Moderately. C

Which of the following may affect the rate constant (k) fro a reaction :

• Change in concentration. A
• Change in pressure. B
• Change in pH. C
• Change in temperature. D

The unit rate of constan K ismole^-1 dm³S^-1for a chemical reaction, the order of reaction is :

• 3 A
• 2 B
• 1 C
• 0 D

Which of the following is not affected by light

• 
  A
• 
  B
• 
  C
• 
  D

A white precipitate ofsilver chlorideimmediately formed on additionof :

• Silver nitrate solution to sodium chloride solution. A
• Silver chloride solution to sodium nitrate solution. B
• Silver nitrate solution to potassium chloride solution C
• Silver nitrate solution to hydrogen chloride solution. D

Dilatometer method is useful for the reaction that involve :

• Small volume changes in solutions A
• Change in infractive indices B
• Where reactants absorb U.V, visible or infrared radiation C

If the rate equation of a reaction 2A+B-------->Products is , Rate = K[A] [B], and A is present in large excess, then order of reaction is :

• 1 A
• 2 B
• 3 C
• Above D

A white precipitate ofsilver chlorideimmediately formed on additionof :

• Silver nitrate solution to sodium chloride solution. A
• Silver chloride solution to sodium nitrate solution. B
• Silver nitrate solution to potassium chloride solution C
• Silver nitrate solution to hydrogen chloride solution. D

• Zero A
• 253 sec B
• 150 sec C
• 500 sec D

If the rate of decay of radioactive isotope decreases from 200 cpm to 25 cpm after 24 hours, what is its half life :

• 8 hours A
• 6 hours B
• 4 hours C
• 3 hours D

The unit of the rate constant is the same as that of rate of reaction in :

• Third order reaction A
• Second order reaction B
• First order reaction C
• Zero order reaction D

Optical rotation method is sued when

• Reaction involve ions A
• Change of refractive indices B
• Reactions involving change of optical activity C
• None of the above D

When we perform the same reaction by taking two different initial concentrations of a reactant for a second order reaction then

• Reaction becomes exothermic A
• Energy of activation is different B
• Mechanism of reaction is changed C
• Half life period is changed D

Factor which slows down the rate of reaction is

• Small size of the particles of the reactant A
• High temperature of reaction B
• More concentration of reactant C
• Lowering the temperature D

Platinum is poisoned by

• Arsenic A
• Silver B
• Argon C
• Zinc D

which one of the following is a heteroheneous catalysis

• 
  A
• 
  B
• 
  C
• 
  D

In thermal decomposition of N₂O the half life period for two different initial concentrations of N₂O are

(i) 255 second for initial N₂O 290 mm Hg

(ii) 212 second for initial N₂O 360 mm Hg then it is

• Zero order A
• First order B
• Second order C
• Third order D

The factor which effect the rate of reaction

• Nature of reactants A
• Surface area B
• Light C
• All of the above D

______ are called biocatalysts

• Organic acids A
• Organic bases B
• Enzymes C
• All D

Complex protein molecules which catalyses the organic reactions in the living cells are called

• Living organisms A
• Enzymes B
• Viruses C
• Bacteria D

Which statement is not correct

• Enzymes catalyst a specific reaction A
• Enzymes show catalytic activity at a specific temperature B
• The catalytic activity of enzymes is stopped if optimum pH is changed C
• The catalytic activity is poisoned by a co-enzymes D

• 
  A
• 
  B
• 
  C
• 
  D

If initial concentration of the reactants and half life period of the reaction is known, then we can determine

• Average rate of reaction A
• Order of reaction B
• Rate constant k C
• Instantaneous rate D

It rate law of an equation is written asdx/dt=K[A][B] ?

• Reaction is independent of the concentration of A and B. A
• Product is decreasing with passage of time. B
• Reactant in increasing with passage of time. C
• Reactant is increasing with passage of time. D

With the progressive of the reaction the slope of the curve between concentration of product and time

• Gradually becomes more steep A
• Gradually becomes less steep B
• No change occurs in slope C
• None of these occurs D

The number of atoms or molecules whose concentrations determine the rate of the reaction is called

• Molecularity A
• Order B
• Rate of reaction C
• Rate constant D

Which of the following reactions occur at moderate rate :

• Rusting of iron A
• Chemical weathering of stone work of buildings by acidic gases in atmosphere. B
• Hydrolysis of an ester C
• Fermentation of sugars D

The change in concentration of reactant or product per unit time is called :

• Rate constant. A
• Rate of reaction. B
• Rate equation. C
• Rate law. D

In zero order reaction, the rate is independent of :

• Temperature of reaction A
• Concentration ofreactants B
• Concentration of products C
• None of these. D