Oxidation Number Method

Q.

Give balanced equation for the action of heat on silver nitrate.

Q.

What is an intermediate complex theory of catalysis?

Q. Consider a redox reaction :

$xN{a}_{2}HAs{O}_3+yNaBr{O}_3+zHCl\to NaBr+H_{3}As{O}_4+NaCl$

where $x,y,z$ are the stoichiometric coefficients of $N{a}_{2}HAs{O}_3,NaBr{O}_3,HCl$ respectively.
The value of $x+y+z$ in the above balanced redox reaction is :

1. $3$
2. $9$
3. $10$
4. $12$

Q. A 4 mol mixture of Mohr’s salt and $F{e}_2(S{O}_4{)}_3$ requires 400 ml of $0.5{\text{M KMnO}}_4$ for complete oxidation in an acidic medium. The percentage of Mohr’s salt in the mixture is:

1. 40 %
2. 5 %
3. 50 %
4. 25 %

Q. The given unbalanced redox reaction
$S_2{O}_3^{2-}+S{b}_2{O}_5+H^{+}\to SbO+H_{2}S{O}_3$
is balanced by oxidation number method. The stoichiometric coefficient of $S{b}_2{O}_5$ and $SbO$ respectively, will be:

1. $2,4$
2. $4,8$
3. $3,6$
4. $1,2$

Q. What is the oxidation number of $Mn$ in $KMn{O}_4$ and of $S$ in $N{a}_2{S}_2{O}_3$ ?

1. $+7,-2$
2. $+5,-2$
3. $+7,+2$
4. $+5,+2$

Q. What would be the stoichiometric coefficient of $P$ and $HN{O}_3$ respectively, in the net balanced equation for the given redox reaction:
$P+HN{O}_3\to HP{O}_3+NO+H_{2}O$

1. $5,3$
2. $1,1$
3. $2,3$
4. $3,5$

Q.

How do you write redox reactions ?

Q.

What happens when (give balanced chemical equation also) :

Ammonia is passed over hot copper oxide?

Q. Balance the following chemical equation:$\underset{\left(aq\right)}{C{r}_2{O}_7^{2-}}+\underset{\left(aq\right)}{S{O}_3^{2-}}\to \underset{\left(aq\right)}{C{r}^{3+}}+\underset{\left(aq\right)}{S{O}_4^{2-}}$ (Acidic medium)

1. $\underset{\left(aq\right)}{C{r}_2{O}_7^{2-}}+\underset{\left(aq\right)}{3S{O}_3^{2-}}+\underset{\left(aq\right)}{H^{+}}\to \underset{\left(aq\right)}{2C{r}^{3+}}+\underset{\left(aq\right)}{3S{O}_4^{2-}}+\underset{\left(aq\right)}{4H_{2}O}$
2. $\underset{\left(aq\right)}{C{r}_2{O}_7^{2-}}+\underset{\left(aq\right)}{S{O}_3^{2-}}+\underset{\left(aq\right)}{8H^{+}}\to \underset{\left(aq\right)}{2C{r}^{3+}}+\underset{\left(aq\right)}{3S{O}_4^{2-}}+\underset{\left(aq\right)}{4H_{2}O}$
3. $\underset{\left(aq\right)}{C{r}_2{O}_7^{2-}}+\underset{\left(aq\right)}{3S{O}_3^{2-}}+\underset{\left(aq\right)}{8H^{+}}\to \underset{\left(aq\right)}{2C{r}^{3+}}+\underset{\left(aq\right)}{3S{O}_4^{2-}}+\underset{\left(aq\right)}{4H_{2}O}$
4. $\underset{\left(aq\right)}{C{r}_2{O}_7^{2-}}+\underset{\left(aq\right)}{3S{O}_3^{2-}}+\underset{\left(aq\right)}{8H^{+}}\to \underset{\left(aq\right)}{C{r}^{3+}}+\underset{\left(aq\right)}{3S{O}_4^{2-}}+\underset{\left(aq\right)}{4H_{2}O}$

Q. Find the equivalent weight of $K_{2}C{r}_2{O}_7^{2-}$ in the given reaction, if the molar mass of $C{r}_2{O}_7^{2-}$ is 'M' ?
$K_{2}C{r}_2{O}_7^{2-}\stackrel{H^{+}}{\to }C{r}^{3+}$

1. $\frac{M}{6}$
2. $\frac{M}{3}$
3. $M$
4. $2M$

Q. Which of the following equations is a balanced one?

1. $5Bi{O}_3^{-}+22H^{+}+M{n}^{2+}\to 5B{i}^{3+}+7H_{2}O+Mn{O}_4^{-}$
2. $5Bi{O}_3^{-}+14H^{+}+2M{n}^{2+}\to 5B{i}^{3+}+7H_{2}O+2Mn{O}_4^{-}$
3. $2Bi{O}_3^{-}+4H^{+}+M{n}^{2+}\to 2B{i}^{3+}+2H_{2}O+Mn{O}_4^{-}$
4. $6Bi{O}_3^{-}+12H^{+}+3M{n}^{2+}\to 6B{i}^{3+}+6H_{2}O+3Mn{O}_4^{-}$

Q. Using Oxidation-number method, find the net ionic equation for the following reaction in basic medium:
$Mn\left(OH{)}_2\right(s)+Mn{O}_4^{-}(aq)\to Mn{O}_2(s)$

1. $6Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+O{H}^{-}$
2. $4Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 4Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$
3. $2Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$
4. $3Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$

Q. Write balanced net ionic equation for the following reaction in basic solution:
$Mn\left(OH{)}_2\right(s)+Mn{O}_4^{-}(aq)\to Mn{O}_2(s)$

1. $6Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+O{H}^{-}$
2. $4Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 4Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$
3. $2Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$
4. $3Mn\left(OH{)}_2\right(s)+2Mn{O}_4^{-}(aq)\to 5Mn{O}_2(s)+2H_{2}O+2O{H}^{-}$

Q. Which ordering of compounds is according to the decreasing order of the oxidation state of nitrogen?

1. $HN{O}_3,NO,N{H}_{4}Cl,N_2$
2. $HN{O}_3,NO,N_2,N{H}_{4}Cl$
3. $HN{O}_3,N{H}_{4}Cl,NO,N_2$
4. $NO,HN{O}_3,N{H}_{4}Cl,N_2$

Q. The reaction of the permanganate ion with the oxalate ion in acidic solution forms manganese(II) ion and carbon dioxide. What is the stoichiometric coefficient in front of manganese(II) in the balanced redox equation?
$Mn{O}_4^{-}+C_2{O}_4^{2-}\to M{n}^{2+}+C{O}_2$

1. 2
2. 1
3. 3
4. 5

Q. What will be the ratio $\frac{n_{C{r}_2{O}_7^{2-}}}{n_{S{O}_3^{2-}}}$ when the following redox reaction
$C{r}_2{O}_7^{2-}\left(aq\right)+S{O}_3^{2-}\left(aq\right)\to C{r}^{3+}\left(aq\right)+S{O}_4^{2-}\left(aq\right)$
is balanced in an acidic medium. Where $n$ represents the stoichiometric coefficient of the respective species.

1. $2:1$
2. $1:3$
3. $1:2$
4. $2:3$

Q. The given unbalanced redox reaction
$S_2{O}_3^{2-}+S{b}_2{O}_5+H^{+}\to SbO+H_{2}S{O}_3$
is balanced by oxidation number method. The stoichiometric coefficient of $S{b}_2{O}_5$ and $SbO$ respectively, will be:

1. $2,4$
2. $4,8$
3. $3,6$
4. $1,2$

Q. What are the stoichiometric coefficients in the balanced redox reaction only for the species in the unbalanced reaction respectively.This reaction is used by the Breathalyzer to detect ethyl alcohol in a driver's breath?
$C_2{H}_{5}OH+C{r}_2{O}_7^{2-}\to C{H}_{3}COOH+C{r}^{3+}$

1. Reactants: 3, 4; products: 3, 8
2. Reactants: 2, 2; products: 2, 4
3. Reactants: 3, 1; products: 3, 2
4. Reactants: 3, 2; products: 3, 4

Q. What would be the coefficient of $H^{+}$ and $H_{2}O$ respectively in the balanced net ionic equations for the given redox reactions in acidic solution:
$S_4{O}_6^{2-}\left(aq\right)+Al\left(s\right)\to H_{2}S\left(aq\right)+A{l}^{3+}\left(aq\right)$

1. 20, 6
2. 6, 20
3. 10, 4
4. 4, 10

Q. Match the reactions given in List I with the number of electrons lost or gained in List II
$\begin{array}{cccc}& Column-I& & Column-II\\ & Reaction& & Numberofelectronslostorgained\\ \left(P\right)& Mn(OH{)}_2+H_2{O}_2\to Mn{O}_2+2H_{2}O& \left(1\right)& 8\\ \left(Q\right)& AlC{l}_3+3K\to Al+3KCl& \left(2\right)& 2\\ \left(R\right)& 3Fe+4H_{2}O\to F{e}_3{O}_4+4H_2& \left(3\right)& 3\\ \left(S\right)& 3H_{2}S+2HN{O}_3\to 3S+2NO+4H_{2}O& \left(4\right)& 6\end{array}$

1. $\begin{array}{cccc}P& Q& R& S\\ 2& 3& 1& 4\end{array}$
2. $\begin{array}{cccc}P& Q& R& S\\ 3& 2& 1& 4\end{array}$
3. $\begin{array}{cccc}P& Q& R& S\\ 2& 1& 3& 4\end{array}$
4. $\begin{array}{cccc}P& Q& R& S\\ 1& 4& 3& 2\end{array}$

Q. Which one is balanced net ionic equations for the following reactions in acidic solution:
$HN{O}_2\left(aq\right)\to N{O}_3^{-}+NO\left(g\right)$

1. $3HN{O}_2\left(aq\right)\to N{O}_3^{-}\left(aq\right)+2NO\left(g\right)+H_{2}O+H^{+}\left(aq\right)$
2. $4HN{O}_2\left(aq\right)\to 3N{O}_3^{-}+2NO\left(g\right)+H_{2}O+H^{+}+e^{-}$
3. $3HN{O}_2\left(aq\right)\to N{O}_3^{-}+2NO\left(g\right)+H_{2}O+H^{+}+e^{-}$
4. $4HN{O}_2\left(aq\right)\to N{O}_3^{-}+2NO\left(g\right)+H_{2}O+H^{+}+e^{-}$

Q. What will be the value of w, x, y, z respectively in balanced net equation for the following reaction in basic solution :
$wT{l}_2{O}_3\left(s\right)+xN{H}_{2}OH\left(aq\right)\to yTlOH\left(s\right)+z{N}_2\left(g\right)$

1. 1, 4, 2, 2
2. 4, 3, 2, 1
3. 2, 3, 4, 1
4. 1, 4, 3, 2

Q. $Cl{O}_2+Sb{O}_2^{-}\to Cl{O}_2^{-}+Sb(OH{)}_6^{-}$
The balanced form of the above reaction in basic medium using oxidation number method is:

1. $2Cl{O}_2+Sb{O}_2^{-}+2O{H}^{-}\to 2Cl{O}_2^{-}+Sb(OH{)}_6^{-}+2H_{2}O$
2. $Cl{O}_2+Sb{O}_2^{-}+2H_{2}O+O{H}^{-}\to Cl{O}_2^{-}+Sb(OH{)}_6^{-}$
3. $2Cl{O}_2+Sb{O}_2^{-}+2H_{2}O+2O{H}^{-}\to 2Cl{O}_2^{-}+Sb(OH{)}_6^{-}$
4. $2Cl{O}_2+4Sb{O}_2^{-}+2O{H}^{-}\to Cl{O}_2^{-}+4Sb(OH{)}_6^{-}+3H_{2}O$

Q. What is the oxidation number of $Mn$ in $KMn{O}_4$ and of $S$ in $N{a}_2{S}_2{O}_3$ ?

1. $+7,-2$
2. $+5,-2$
3. $+7,+2$
4. $+5,+2$

Q. What would be the coefficient of $H^{+}$ and $H_{2}O$ respectively in the balanced net ionic equations for the given redox reactions in acidic solution:
$S_4{O}_6^{2-}\left(aq\right)+Al\left(s\right)\to H_{2}S\left(aq\right)+A{l}^{3+}\left(aq\right)$

1. 20, 6
2. 6, 20
3. 10, 4
4. 4, 10

Q. For the redox reaction:
$I{O}_3^{-}\left(aq\right)+Rd\left(s\right)+H_{2}O\to Rd{O}_4^{-}\left(aq\right)+I^{-}\left(aq\right)+H^{+}$
The correct coefficient of the $I{O}_3^{-}$, $H_{2}O$ and $H^{+}$ is :

1. 1, 5, 10
2. 5, 1, 10
3. 7, 3, 6
4. 7, 6, 4

Q. What will be the oxidation number of underlined element : $KAl(\underset{–}{S}{O}_4{)}_2.12H_{2}O$

1. $+2$
2. $+6$
3. $-2$
4. $+3$

Q.

Write the chemical equation of how nitrogen dioxide is formed from a metallic nitrate?

Q. What would be the value of stoichiometric coefficients of $Mg$ and $V{O}_4^{3-}$ respectively, in the balanced net ionic equation for the given redox reaction in acidic medium:
$Mg\left(s\right)+V{O}_4^{3-}\left(aq\right)\to M{g}^{2+}\left(aq\right)+V^{2+}\left(aq\right)$

1. 3, 2
2. 8, 16
3. 1, 1
4. 5, 10