Valency and Oxidation State

Q.

Predict the oxidation number of nitrogen in ammonia (${\mathrm{NH}}_3$).

Q. The maximum n-factor $\left(n_f\right)$ for $H_{3}P{O}_3$ and $H_{3}P{O}_4$ respectively is:

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

Q.

What is the oxidation number of carbon in ${\mathrm{CO}}_2$?

Q. The oxidation number of phosphorus in $M{g}_2{P}_2{O}_7$ is:

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

Q. Find the n-factor of the $\left(FeS{O}_4\right)$ in the following chemical changes.
$(FeS{O}_4\to F{e}_2{O}_3)$

1. \N
2. 1
3. -1
4. $\frac{1}{2}$

Q. If 1.2g of metal displace 1.12 lit hydrogen at normal temperature & pressure, equivalent weight of metal would be

1. $24$
2. $12$
3. $1.2\times 11.2$
4. $1.2÷112$

Q. Calculate oxidation state of $Ag$ in $Ag\left[\right(S_2{O}_3{)}_2{]}^{3-}$ molecule

1. $+1$
2. $0.5$
3. $-1$
4. $-2$

Q. Calculate the n factor of $N{H}_{4}Cl$ for the following change:
$N{H}_{4}Cl+NaN{O}_2\to N_2+2H_{2}O+NaCl$

1. 6
2. 3
3. 2
4. 4

Q. Oxidation number of $Fe$ in $\left[Fe\right(SCN){]}^{+2}$ and $\left[Fe\right(H_{2}O{)}_6{]}^{+3}$ would be respectively-

1. +3 and +3
2. +3 and -3
3. +2 and +2
4. +2 and -2

Q.

What is the difference between charge and oxidation number?

Q. In the reaction, $I_2+2S_2{O}_3^{2-}\to 2I^{-}+S_4{O}_6^{2-}$
equivalent weight of iodine is

1. $\frac{1}{2}ofmolecularweight$
2. $Molecularweight$
3. $\frac{1}{4}ofmolecularweight$
4. $Noneofthese$

Q. Oxidation number of nitrogen "$N$" in $N_2{H}_5^{+}$​ is :

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

Q. Find the valence factor for following acids
$\left(i\right)H_{3}P{O}_3$
$\left(ii\right)H_{3}B{O}_3$

1. $\left(i\right)1or2$
   $\left(ii\right)1$
2. $\left(i\right)1$
   $\left(ii\right)1or2$
3. $\left(i\right)3$
   $\left(ii\right)3$
4. None of the above

Q. What is the oxidation number of $Zn$ in the following molecule:
$Zn{O}_2^{2-}$

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

Q. In the equation $H_{2}S+2HN{O}_3\to 2H_{2}O+2N{O}_2+S$ The equivalent weight of hydrogen sulphide is

1. 16
2. 68
3. 34
4. 17

Q. Find the n-factor in the following chemical changes.
$K_{2}C{r}_2{O}_7\stackrel{H^{+}}{\to }C{r}^{3+}$

1. 1
2. \N
3. 3
4. 6

Q. Oxidation number of oxygen in $O_2$ molecule is

1. + 1
2. \N
3. + 2
4. - 2

Q. When a sulphur atom becomes a sulphide ion

1. There is no change in the composition of atom
2. It gains two electrons
3. The mass number changes
4. None of these

Q. Calculate the oxidation number of Chlorine $\left(Cl\right)$ in
$Ca(Cl{O}_2{)}_2$

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

Q. Find the number of electrons lost or gained in the following reaction
a) $Mn(OH{)}_2+H_2{O}_2\to Mn{O}_2+2H_{2}O$
b) $AlC{l}_3+3K\to Al+3KCl$ respectively.

1. 2, 3
2. 3, 2
3. 4, 2
4. 0, 0

Q. Calculate the total n-factor for the oxidation half reaction given below:
$Fe{C}_2{O}_4\left(aq\right)\to F{e}^{3+}\left(aq\right)+C{O}_2\left(g\right)$

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

Q. In the conversion $B{r}_2\to Br{O}_3^{-}$, the oxidation state of Bromine changes from :

1. $-1$ to $+1$
2. $-5$ to $+5$
3. $0$ to $+5$
4. $-5$ to $0$

Q. Calculate the total n-factor for the reduction half reaction given below:
$F{e}_2(S{O}_4{)}_3⟶FeO+S{O}_2$

1. 4
2. 8
3. 6
4. 5

Q. What will be the value of n-factor $\left(n_f\right)$ or valence factor of $P$ in $C{a}_3{P}_2$ and $H_{3}P{O}_4$ respectively for the following change:

$C{a}_3{P}_2⟶H_{3}P{O}_4$

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

Q. What will be the n-factor $\left(n_f\right)$ for $F{e}_2{O}_3$ in the following chemical change :
$F{e}_2{O}_3\to FeS{O}_4$

1. $0$
2. $1$
3. $2$
4. $3$

Q. The oxidation state of $Fe$ in $FeS{O}_4$.$(N{H}_4{)}_{2}S{O}_4$.$6H_{2}O$ is .

1. 2
2. 3
3. 1

Q. In the following redox reaction $C{r}_2{O}_7^{2-}+F{e}^{2+}\to F{e}^{3+}+C{r}^{3+}$ One mole of $C{r}_2{O}_7^{2-}$ oxidises?

1. 6 mole of $F{e}^{2+}$
2. 1 mole of $F{e}^{2+}$
3. 4 mole of $F{e}^{2+}$
4. 3 mole of $F{e}^{2+}$

Q. Which of the following statements regarding $H_{2}S{O}_5$ is/are incorrect?

1. The oxidation number of sulphur is +6
2. Two oxygen atoms are present in form of peroxide
3. Three oxygen atoms are present in form of oxide
4. The oxidation number of sulphur is +8

Q. Calculate the mass of $K_{2}C{r}_2{O}_7$ required to produce $252g{I}_2$ from $KI$ solution.
$K_{2}C{r}_2{O}_7+KI\to C{r}^{3+}+I_2$

(Molar mass of $K_{2}C{r}_2{O}_7$ is $294gmo{l}^{-1}$)

Q.

Calculate the oxidation number of the central atom in ${\mathrm{FeCO}}_5.$