Redox Reactions

Q.

Ferric oxide reacts with aluminum to produce aluminum oxide and iron. The balanced chemical equation for the given reaction is:

${\mathrm{Fe}}_2{\mathrm{O}}_3+2\mathrm{AI}\to {\mathrm{Al}}_2{\mathrm{O}}_3+2\mathrm{Fe}$

Which of the following substances is oxidized in the given reaction?

1. ${\mathrm{Al}}_2{\mathrm{O}}_3$

2. ${\mathrm{Fe}}_2{\mathrm{O}}_3$

3. $\mathrm{Al}$

4. $\mathrm{Fe}$

Q.

The rusting of iron is an example of-

Q.

An Account For The Following ${\mathrm{Cu}}^{+}$ Is Unstable In An Aqueous Solution.

Q. For the reaction,
$A+2B\to 2C$
If 3 moles of A react with 6 moles of B, then:

1. 8 moles of C are formed
2. 5 moles of C are formed
3. 10 moles of C are formed
4. 6 moles of C are formed

Q. In $Fe\left(II\right)–Mn{O}_4^{-}$ titration, $HN{O}_3$ is not used because:

1. It oxidizes $M{n}^{(}2+)$
2. It reduces $Mn{O}_4^{-}$
3. It oxidizes $F{e}^{2+}$
4. It reduces $F{e}^{3+}$ formed

Q.

The divalent metal whose oxide is reduced to metal by electrolysis of its fused salt is ___ $(Al/Na/Mg/K)$

Q. Which one of the following reactions is not an example of redox reaction

1. $C{l}_2+2H_{2}O+S{O}_2\to 4H^{+}+S{O}_4^{2-}+2C{l}^{-}$
2. $C{u}^{++}+Zn\to Z{n}^{++}+Cu$
3. $2H_2+O_2\to 2H_{2}O$
4. $HCl+H_{2}O\to H_3{O}^{+}+C{l}^{-}$

Q.

A redox reaction is:

1. Proton transfer reaction

2. Ion combination reaction

3. A reaction in solution

4. Electron transfer reaction

Q. Which of the following reactions is an example of a redox reaction?

1. $Xe{F}_2+P{F}_5\to [XeF{]}^{+}P{F}_6^{-}$
2. $Xe{F}_6+H_{2}O\to XeO{F}_4+2HF$
3. $Xe{F}_6+2H_{2}O\to Xe{O}_2{F}_2+4HF$
4. $Xe{F}_4+O_2{F}_2\to Xe{F}_6+O_2$

Q. In which of the following reaction (s) $H_{2}S{O}_4$ can't act as an oxidising agent?

1. $C_{12}{H}_{22}{O}_{11}\stackrel{H_{2}S{O}_4}{\to }12C+11H_{2}O$
2. $S+2H_{2}S{O}_4\to 3S{O}_2+2H_{2}O$
3. $Cu+2H_{2}S{O}_4\to CuS{O}_4+S{O}_2+2H_{2}O$
4. All of the above

Q. Which of the following cannot decolourise the iodine solution?

1. Excess of chlorine water
2. Excess of $N{a}_2{S}_2{O}_3$ solution
3. Excess of $B{r}^{-}$ solution
4. Excess of NaOH solution

Q.

25g of 80% pure Ca$C{O}_3$ is made to react with excess of HCl. Calculate volume of $C{O}_2$ evolved at NTP.

1. 2.28 L

2. 1.18 L

3. 3.38 L

4. 4.48 L

Q. In the reaction,
$Cu+H_{2}S{O}_4\to CuS{O}_4+H_{2}O+S{O}_2$

1. $H^{+}$ is an oxidation agent
2. $S{O}_4^{2-}$ is an oxidising agent
3. Both (a) and (b) correct
4. None of these

Q. A $8gm$ sample of iron are containing $V\%$ (by wt) of iron $F{e}^{2+}$ was present in $1L$ solution. This solution required $VmL$ of a $KMn{O}_4$ solution for oxidation of $F{e}^{2+}$in acidic medium. If in another titration $20mL$ of same $KMn{O}_4$ is required, for oxidation of $20mL{H}_2{O}_2$ in acidic medium. Find volume strength of $H_2{O}_2$

Q. For the reactions,
$B{r}_2+O{H}^{-}\to B{r}^{-}+Br{O}_3^{-}+H_{2}O$
what is the equivalent weight of $B{r}_2$ ?

1. $M/8$
2. $M/5$
3. $3M/5$
4. $5M/8$

Q. In the reaction,
$Cu+H_{2}S{O}_4\to CuS{O}_4+H_{2}O+S{O}_2$

1. $H^{+}$ is an oxidation agent
2. $S{O}_4^{2-}$ is an oxidising agent
3. Both (a) and (b) correct
4. None of these

Q. Identify oxidant and reductant in the following reaction:
$Cu+4HN{O}_3\left(dil\right)\to Cu(N{O}_3{)}_2+2H_{2}O+2NO$

1. $HN{O}_3,Cu$
2. $Cu,H_{2}O$
3. $Cu,HN{O}_3$
4. None of these

Q. Following reaction describe the rusting of iron,
$4Fe+3O_2\to 4F{e}^{3+}+6O^{2-}$
Which one of the following statement is incorrect?

1. This is an example of a redox reaction
2. Metallic iron is a reducing agent
3. $O_2$ is an oxidising agent
4. Metallic iron is reduced to $F{e}^{3+}$

Q. Identify the oxidant and the reductant in the following reaction respectively:
$Cu+HN{O}_3\left(dil\right)\to Cu(N{O}_3{)}_2+H_{2}O+NO$

1. $HN{O}_3$ $\&$ $NO$
2. $NO$ $\&$ $HN{O}_3$
3. $Cu$ $\&$ $HN{O}_3$
4. $HN{O}_3$ $\&$ $Cu$

Q.

Reduction involves :

1. Addition of Hydrogen

2. Addition of any electropositive element

3. Removal of oxygen

4. Removal of any electronegative element

Q. Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?

1. $Cu+2H_{2}S{O}_4\to CuS{O}_4+S{O}_2+2H_{2}O$
   
2. $S+2H_{2}S{O}_4\to 3S{O}_2+2H_{2}O$
   
3. $C+2H_{2}S{O}_4\to C{O}_2+2S{O}_2+2H_{2}O$
   
4. $Ca{F}_2+H_{2}S{O}_4\to CaS{O}_4+2HF$

Q. $Z{n}^{2+}\left(aq\right)+2e\to Zn\left(s\right)$. This is

1. Oxidation
2. Reduction
3. Redox reaction
4. None of these

Q. Identify the oxidant and the reductant in the following reaction respectively:
$2KMn{O}_4+10KCl+8H_{2}S{O}_4\to 2MnS{O}_4+6K_{2}S{O}_4+8H_{2}O+5C{l}_2$

1. $KMn{O}_4$ $\&$ $KCl$
2. $KMn{O}_4$ $\&$ $H_{2}S{O}_4$
3. $MnS{O}_4$ $\&$ $KMn{O}_4$
4. $KCl$ $\&$ $KMn{O}_4$

Q. The minimum quantity of $H_{2}S$ needed to precipitate $63.5g$ of $C{u}^{2+}$ will be nearly -

1. $63.5g$
2. $31.75g$
3. $34.0g$
4. $2.0g$

Q. Identify oxidant and reductant in the following reaction:
$Cu+4HN{O}_3\left(dil\right)\to Cu(N{O}_3{)}_2+2H_{2}O+2NO$

1. $HN{O}_3,Cu$
2. $Cu,H_{2}O$
3. $Cu,HN{O}_3$
4. None of these

Q. For the reactions,
$B{r}_2+O{H}^{-}\to B{r}^{-}+Br{O}_3^{-}+H_{2}O$
what is the equivalent weight of $B{r}_2$ ?

1. $M/8$
2. $M/5$
3. $3M/5$
4. $5M/8$

Q. In which of the following reaction (s) $H_{2}S{O}_4$ can't act as an oxidising agent?

1. $C_{12}{H}_{22}{O}_{11}\stackrel{H_{2}S{O}_4}{\to }12C+11H_{2}O$
2. $S+2H_{2}S{O}_4\to 3S{O}_2+2H_{2}O$
3. $Cu+2H_{2}S{O}_4\to CuS{O}_4+S{O}_2+2H_{2}O$
4. All of the above

Q. Hot concentrated sulphuric acid is a moderately strong oxidizing agent. Which of the following reactions does not show oxidizing behaviour?

1. $Cu+2H_{2}S{O}_4\to CuS{O}_4+S{O}_2+2H_{2}O$
   
2. $S+2H_{2}S{O}_4\to 3S{O}_2+2H_{2}O$
   
3. $C+2H_{2}S{O}_4\to C{O}_2+2S{O}_2+2H_{2}O$
   
4. $Ca{F}_2+H_{2}S{O}_4\to CaS{O}_4+2HF$

Q. Which of the following can function as an oxidizing as well as a reducing agent ?

1. $H_{2}S$
2. $H_{2}S{O}_4$
3. $H_2{O}_2$
4. $S{O}_3$

Q. Dichromate ion in acidic medium oxidises stannous ion as :
$xS{n}^{2+}+yC{r}_2{O}_7^{2-}+z{H}^{+}\to aS{n}^{4+}+bC{r}^{3+}+c{H}_{2}O$

1. The value of $x:y$ is $1:3$
2. The value of $x+y+z$ is $18$
3. $a:b$ is $3:2$
4. The value of $z-c$ is $7$