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Assertion : For a first order reaction, the degree of dissocation is equal to $(1 - e^{- k t})$

Reason : For a first order reaction, the pre-exponential factor in the Arrhenius equation has the dimension of $t i m e^{- 1}$

A. If both the assertion and the reason are true and the reason is a correct explanation of the assertion B. If both the assertion and reason are true but the reason is not a correct explanation of the assertion C. If the assertion is true but the reason is false D. If both the assertion and reason are false

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Explanation

(B). For a first order reaction,

$[A]_{f} [A]_{0} e x p (- k t)$

$[A]_{0} - [A]_{f} = [A]_{0} - [A]_{0} e x p (- k t) [A]_{0} (1 - e x p (- k t) o r \frac{[A]_{0} - [A]_{f}}{[A]_{0}} (1 - e x p (- k t)$

So, degree of dissocation = (1 – exp (–kt)

For a first order reaction,

$k = A e x p (- E_{a} / R T) = A e x p (\frac{J m o l^{- 1}}{J m o l^{- 1} K^{- 1} K})$

Thus, the units of A are the same as that for k. For a first order reaction, the units of k are those of time $^{- 1}$ . So the units of A are also those of time $^{- 1}$

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Which acts as inhibitor for knocking in combustion of petrol?

(C₂H₅)₄Pb

Ni(CO)₄

both (a) and (b)

none of these

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Explanation

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Which does not show Tyndall effect?

Emulsion

Blood

milk

sugar solution

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Explanation

(d) sugar solution does not shows Tyndall effect. Rest all the options shows this effect.

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Among the following surfactant molecules, the surfactant that forms micelles in aqueous solution at the lower CMC at ambient condition is:

${CH}_{3} {({CH}_{2})}_{15} N^{+} {({CH}_{3})}_{3} {Br}^{-}$

${CH}_{3} {({CH}_{2})}_{11} {OSO}_{3}^{-} {Na}^{+}$

${CH}_{3} {({CH}_{2})}_{6} {COO}_{}^{-} {Na}^{+}$

${CH}_{3} {({CH}_{2})}_{11} N^{+} {({CH}_{3})}_{3} {Br}^{-}$

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Explanation

(a) More is the hydrophobic character in surfactant molecule lesser is CMC in aqueous solution.

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Butter is a colloid form in which:

fat is dispersed in solid casein

fat globules are dispersed in water

water is dispersed in fat

suspension of casein is in water

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Explanation

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The cotterells precipitator is used to :

neutralize charge on carbon particles in air in smoke

coagulate carbon atoms of smoke

bring in cataphoresis in carbon particles

all of the above

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Explanation

(d) The negatively charged carbon particles in air (smoke) are moved towards anode due to cataphoresis, where they are neutralized to left free air. The process is used to control air pollution.

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A liquid aerosol is a colloidal system of:

a liquid dispersed in a solid

a liquid dispersed in a gas

a gas dispersed in a liquid

a solid dispersed in a gas

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Explanation

(b) Liquid aerosol involves liquid dispersed in gas, e.g., cloud, fog , mist, etc.

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Negative catalyst or inhibitor is one:

which retards the rate of reaction

takes the reaction in forward direction

promotes the side reaction

none of the above

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Explanation

(a) The definition of negative catalyst.

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Alum helps in purifying water by:

forming Si complex with clay particles

sulphate part which combines with the dirt and removes it

aluminium which coagulates the mud particles

making mud water soluble

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Explanation

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Which of the following does not form anionic micelle?

C₁₂H₂₅COONa

C₁₂H₂₅SO₄Na

C₁₂H₂₅SO₃Na

C₁₂H₂₅(NH₃)₃Cl

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Explanation

(d) In a, b, c anionic micelle is formed.

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