121. The first ionisation energies of the elements of the first transition series $$\left( {Ti\,\,{\text{to}}\,\,Cu} \right)$$
A
increases as the atomic number increases
B
decreases as the atomic number increases
C
do not show any change as the addition of electrons takes place in the inner $$\left( {n - 1} \right)d$$ orbitals
D
increases from $$Ti$$ to $$Mn$$ and then decreases from $$Mn$$ to $$Cu$$
Answer :
increases as the atomic number increases
122. Potassium dichromate when heated with concentrated sulphuric acid and a soluble chloride, gives brown-red vapours of :
A
$$Cr{O_3}$$
B
$$CrC{l_3}$$
C
$$Cr{O_2}C{l_2}$$
D
$$C{r_2}{O_3}$$
Answer :
$$Cr{O_2}C{l_2}$$
123. The common oxidation state shown by Europium in their compounds is
A
+ 1
B
+ 3
C
+ 5
D
+ 6
Answer :
+ 3
124. The element with which of the following outer electron configuration may exhibit the largest number of oxidation states in its compounds :
A
$$3{d^5}4{s^2}$$
B
$$3{d^8}4{s^2}$$
C
$$3{d^7}4{s^2}$$
D
$$3{d^6}4{s^2}$$
Answer :
$$3{d^5}4{s^2}$$
125. Which pair gives $$C{l_2}$$ at room temperature?
A
$$HC{l_{\left( {conc.} \right)}} + KMn{O_4}$$
B
$$NaCl + {H_2}S{O_{4\left( {conc.} \right)}}$$
C
$$NaCl + Mn{O_2}$$
D
$$NaCl + HN{O_{3\left( {conc.} \right)}}$$
Answer :
$$HC{l_{\left( {conc.} \right)}} + KMn{O_4}$$
126. When horn silver ore is dissolved in excess of sodium cyanide solution compound formed is
A
$$AgCN$$
B
$$Na\left[ {Ag{{\left( {CN} \right)}_2}} \right]$$
C
$$N{a_2}\left[ {Ag{{\left( {CN} \right)}_3}} \right]$$
D
$$N{a_4}\left[ {Ag{{\left( {CN} \right)}_5}} \right]$$
Answer :
$$Na\left[ {Ag{{\left( {CN} \right)}_2}} \right]$$
127. In the dichromate anion,
A
$$4\,Cr - O\,{\text{bonds}}\,\,{\text{are}}\,{\text{equivalent}}$$
B
$$6\,Cr - O\,{\text{bonds}}\,\,{\text{are}}\,{\text{equivalent}}$$
C
$${\text{all}}\,Cr - O\,{\text{bonds}}\,\,{\text{are}}\,{\text{equivalent}}$$
D
$${\text{all}}\,Cr - O\,{\text{bonds}}\,\,{\text{are}}\,{\text{nonequivalent}}$$
Answer :
$$6\,Cr - O\,{\text{bonds}}\,\,{\text{are}}\,{\text{equivalent}}$$
128.
The basic character of the transition metal monoxides follows the order
$${\text{(}}\,{\text{Atomic Nos}}{\text{.,}}\,Ti = 22,V = 23,Cr = 24,Fe = 26\,)$$
A
$$TiO > VO > CrO > FeO$$
B
$$VO > CrO > TiO > FeO$$
C
$$CrO > VO > FeO > TiO$$
D
$$TiO > FeO > VO > CrO$$
Answer :
$$TiO > VO > CrO > FeO$$
129. While extracting an element from its ore, the ore is grind and leached with $$dil.$$ $$KCN$$ solution to form the soluble product potassium argento- cyanide. The element is
A
lead
B
chromium
C
manganese
D
silver
Answer :
silver
130. $${K_2}C{r_2}{O_7}$$ on heating with aqueous $$NaOH$$ gives
A
$$CrO_4^{2 - }$$
B
$$Cr{\left( {OH} \right)_3}$$
C
$$C{r_2}O_7^{2 - }$$
D
$$Cr{\left( {OH} \right)_2}$$
Answer :
$$CrO_4^{2 - }$$