Q. Corrosion of iron is essentially an electro chemical phenomenon where the cell reactions are:

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A

$Fe$ is oxidized to $Fe ^{3+} \& H_2 O$ is reduced to $O ^{22-}$

B

$Fe$ is oxidized to $Fe^{ 2+}\& H_2 O$ is reduced to $O _{2}-$

C

$Fe$ is oxidized to $Fe ^{2+}\& H_2 O$ is reduced to $OH$ - ions

D

$Fe$ is oxidized to $Fe^{3+}\& H_2 O$ is reduced to $O_2$

Solution:

Explanation: The rusting of iron is $Fe \rightleftarrows Fe ^{2+}+2 e ^{-}$(oxidation)
$H _{2} O +1 / 2 O _{2}+2 e ^{-} \rightleftarrows 2 OH ^{-} \text {(reduction) }$

Questions from KCET 2022

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3. Conductivity of a solution is directly proportional to

4. Which of the following is a Lewis acid ?

5. For the reaction $A+B \rightarrow C+D$, it is found that doubling the concentration of $A$ increases rate 4 times and doubling the concentration of B doubles the reaction rate. What is the overall order of the reaction ?

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1. If for a certain reaction $\Delta_{r}H$ is $30\, kJ\, mol^{-1}$ at $450 \,K$, the value of $\Delta_{r}S$ (in $JK^{-1}\, mol^{-1})$ for which the same reaction will be spontaneous at the same temperature is

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3. An organic compound contains $78 \%$ (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is: [Atomic wt. of $C$ is $12, H$ is $1$]

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4. At standard conditions, if the change in the enthalpy for the following reaction is $-109 \,kJ\, mol^{-1}$ $H_{2(g)}+Br_{2(g)} \to 2HBr_{(g)}$ Given that bond energy of $H_{2}$ and $Br_{2}$ is $435\,KJ\,mol^{-1}$ and $192\,KJ\,mol^{-1}$ , respectively, what is the bond energy (in $KJ \,mol^{-1})$ of $HBr$ ?

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5. The density of 2 M aqueous solution of NaOH is 1.28 g/cm$^3$. The molality of the solution is
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