131.
Consider the reaction :
$${H_2}S{O_3}\left( {aq} \right) + S{n^{4 + }}\left( {aq} \right) + {H_2}O\left( l \right)$$ $$ \to S{n^{2 + }}\left( {aq} \right) + HSO_4^ - \left( {aq} \right) + 3{H^ + }\left( {aq} \right)$$
Which of the following statements is correct ?
A
$$S{n^{4 + }}$$ is the oxidizing agent because it undergoes oxidation
B
$$S{n^{4 + }}$$ is the reducing agent because it undergoes oxidation
C
$${H_2}S{O_3}$$ is the reducing agent because it undergoes oxidation
D
$${H_2}S{O_3}$$ is the reducing agent because it undergoes reduction
Answer :
$${H_2}S{O_3}$$ is the reducing agent because it undergoes oxidation
132. Which compound among the following has lowest oxidation number of chlorine?
A
$$HCl{O_4}$$
B
$$HCl{O_3}$$
C
$$HCl$$
D
$$HOCl$$
Answer :
$$HCl$$
133. Which of the following is not an example of redox reaction?
A
$$CuO + {H_2} \to Cu + {H_2}O$$
B
$$F{e_2}{O_3} + 3CO \to 2Fe + 3C{O_2}$$
C
$$2K + {F_2} \to 2KF$$
D
$$BaC{l_2} + {H_2}S{O_4} \to BaS{O_4} + 2HCl$$
Answer :
$$BaC{l_2} + {H_2}S{O_4} \to BaS{O_4} + 2HCl$$
134.
If a spoon of copper metal is placed in a solution of $$FeS{O_4},$$ what will be the correct observation?
A
Copper is dissolved in $$FeS{O_4}$$ to give brown deposit.
B
No reaction takes place.
C
Iron is deposited on copper spoon.
D
Both copper and iron are precipitated.
Answer :
No reaction takes place.
135.
$${E^ \circ }$$ values of some redox couples are given below. On the basis of these values choose the correct option.
$${E^ \circ }$$ values : $$\frac{{B{r_2}}}{{B{r^ - }}} = + 1.90;\frac{{A{g^ + }}}{{A{g_{\left( s \right)}}}} = + 0.80;$$ $$\frac{{C{u^{2 + }}}}{{C{u_{\left( s \right)}}}} = + 0.34;\frac{{{I_{2\left( s \right)}}}}{{{I^ - }}} = + 0.54\,V$$
A
$$Cu$$ will reduce $$B{r^ - }$$
B
$$Cu$$ will reduce $$Ag$$
C
$$Cu$$ will reduce $${I^ - }$$
D
$$Cu$$ will reduce $$B{r_2}$$
Answer :
$$Cu$$ will reduce $$B{r_2}$$
136. The number of moles of $$KMn{O_4}$$ reduced by one mole of $$KI$$ in alkaline medium is
A
$$\frac{1}{5}$$
B
$$2$$
C
$$\frac{3}{2}$$
D
$$4$$
Answer :
$$2$$
137. A mole of $${N_2}{H_4}$$ loses $$10\,mol$$ of electrons to form a new compound $$Y.$$ Assuming that all the nitrogen appears in the new compound, what is the oxidation state of nitrogen in $$Y?$$ ( There is no change in the oxidation number of hydrogen. )
A
- 1
B
- 3
C
+ 3
D
+ 5
Answer :
+ 3
138.
Consider the following reaction :
$$HCHO + 2{\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + } + 3O{H^ - }$$ $$ \to 2Ag + HCO{O^ - } + 4N{H_3} + 2{H_2}O$$
Which of the following statements regarding oxidation and reduction is correct?
A
$$HCHO$$ is oxidised to $$HCO{O^ - }$$ and $${\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$$ is reduced to $$Ag.$$
B
$$HCHO$$ is reduced to $$HCO{O^ - }$$ and $${\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$$ is oxidised to $$Ag.$$
C
$${\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$$ is reduced to $$Ag$$ while $$O{H^ - }$$ is oxidised to $$HCO{O^ - }.$$
D
$${\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$$ is oxidised to $$N{H_3}$$ while $$HCHO$$ is reduced to $${H_2}O.$$
Answer :
$$HCHO$$ is oxidised to $$HCO{O^ - }$$ and $${\left[ {Ag{{\left( {N{H_3}} \right)}_2}} \right]^ + }$$ is reduced to $$Ag.$$
139. Which of the following substances acts as an oxidising as well as a reducing agent?
A
$$N{a_2}O$$
B
$$SnC{l_2}$$
C
$$N{a_2}{O_2}$$
D
$$NaN{O_2}$$
Answer :
$$NaN{O_2}$$
140.
Which of the following statements is not correct about the given reaction?
\[{{K}_{4}}\left[ Fe{{\left( CN \right)}_{6}} \right]\xrightarrow{\text{Oxidation}}\] $$F{e^{3 + }} + C{O_2} + NO_3^ - $$
A
$$Fe$$ is oxidised from $$F{e^{2 + }}$$ to $$F{e^{3 + }}.$$
B
Carbon is oxidised from $${C^{2 + }}$$ to $${C^{4 + }}.$$
C
$$N$$ is oxidised from $${N^{3 - }}$$ to $${N^{5 + }}.$$
D
Carbon is not oxidised.
Answer :
Carbon is not oxidised.