101. Assuming complete ionisation, same moles of which of the following compounds will require the least amount of acidified $$KMn{O_4}$$ for complete oxidation?
A
$$FeS{O_4}$$
B
$$FeS{O_3}$$
C
$$Fe{C_2}{O_4}$$
D
$$Fe{\left( {N{O_2}} \right)_2}$$
Answer :
$$FeS{O_4}$$
102. Amount of oxalic acid present in a solution can be determined by its titration with $$KMn{O_4}$$ solution in the presence of $${H_2}S{O_4}.$$ The titration gives unsatisfactory result when carried out in the presence of $$HCl,$$ because $$HCl$$
A
gets oxidised by oxalic acid to chlorine
B
furnishes $${H^ + }$$ ions in addition to those from oxalic acd
C
reduces permanganate to $$M{n^{2 + }}$$
D
Oxidises oxalic acid to carbon doxide and water
Answer :
reduces permanganate to $$M{n^{2 + }}$$
103. Which of the following is correct representation of reaction of acidified permanganate solution with sulphurous acid?
A
$$2MnO_4^ - + 5SO_3^{2 - } + 6{H^ + } \to $$ $$5SO_4^{2 - } + 2M{n^{2 + }} + 3{H_2}O$$
B
$$MnO_4^ - + SO_3^{2 - } + 2{H_2}O \to $$ $$S + M{n^{2 + }} + 4{H^ + }$$
C
$$2MnO_4^ - + 5SO_3^{2 - } + 2{H_2}O \to $$ $$4SO_4^{2 - } + S + 2M{n^{2 + }} + 4{H^ + }$$
D
$$3MnO_4^ - + 2SO_3^{2 - } + 2{H_2}O \to $$ $$2S + 3M{n^2} + 4{H^ + }$$
Answer :
$$2MnO_4^ - + 5SO_3^{2 - } + 6{H^ + } \to $$ $$5SO_4^{2 - } + 2M{n^{2 + }} + 3{H_2}O$$
104. Yellow coloured aqueous solution of sodium chromate changes to orange when acidified with sulphuric acid because
A
$${H^ + }$$ ions convert chromate ions to dichromate ions
B
$${H^ + }$$ ions react with sodium chromate to give sodium ions which turn solution orange
C
$$C{r^{3 + }}$$ ions are liberated in the solution which turn the solution orange
D
sodium hydroxide is formed during the reaction which imparts orange colour to the solution
Answer :
$${H^ + }$$ ions convert chromate ions to dichromate ions
105. Although Zirconium belongs to $$4d$$ transition series and Hafnium to $$5d$$ transition series even then they show similar physical and chemical properties because
A
both belong to $$d$$ - block
B
both have same number of electrons
C
both have similar atomic radius
D
both belong to the same group of the periodic table
Answer :
both have similar atomic radius
106. A reduction in atomic size with increase in atomic number is a characteristic of elements of
A
$$d$$ - block
B
$$f$$ - block
C
radioactive series
D
high atomic masses
Answer :
$$f$$ - block
107.
Match the catalysts (Column I) with products (Column II).
A
A - iii; B - iv; C - i; D - ii
B
A - ii; b - iii; C - i; D - iv
C
A - iii; B - i; C - ii; D - iv
D
A - iv; B - iii; C - ii; D - i
Answer :
A - iii; B - i; C - ii; D - iv
108. Which pair of compounds is expected to show similar colour in aqueous medium?
A
$$FeC{l_2}\,{\text{and}}\,CuC{l_2}$$
B
$$VOC{l_2}\,{\text{and}}\,CuC{l_2}$$
C
$$VOC{l_2}\,{\text{and}}\,FeC{l_2}$$
D
$$FeC{I_2}\,{\text{and}}\,MnC{l_2}$$
Answer :
$$VOC{l_2}\,{\text{and}}\,CuC{l_2}$$
.PNG "D and F Block Elements mcq solution image")
.PNG "D and F Block Elements mcq solution image")
109. The magnetic nature of elements depends on the presence of unpaired electrons. Identify the configuration of transition element, which shows highest magnetic moment.
A
$$3{d^7}$$
B
$$3{d^5}$$
C
$$3{d^8}$$
D
$$3{d^2}$$
Answer :
$$3{d^5}$$
110. The correct order of $$E_{\frac{{{M^{2 + }}}}{M}}^ \circ $$ values with negative sign for the four successive elements $$Cr, Mn, Fe$$ and $$Co$$ is
A
$$Fe > Mn > Cr > Co$$
B
$$Cr > Mn > Fe > Co$$
C
$$Mn > Cr > Fe > Co$$
D
$$Cr> Fe > Mn > Co$$
Answer :
$$Mn > Cr > Fe > Co$$