121. Which of the following hydroxide is acidic ?
A
$$Al{\left( {OH} \right)_3}$$
B
$$Ca{\left( {OH} \right)_3}$$
C
$$Tl{\left( {OH} \right)_3}$$
D
$$B{\left( {OH} \right)_3}$$
Answer :
$$B{\left( {OH} \right)_3}$$
122. $$HCl$$ can be prepared by
A
\[NaCl+{{H}_{2}}S{{O}_{4}}\xrightarrow{420\,K}\]
B
\[NaHS{{O}_{4}}+NaCl\xrightarrow{823\,K}\]
C
\[NaN{{O}_{3}}+{{H}_{2}}S{{O}_{4}}\to \]
D
\[\text{both (A) and (B)}\]
Answer :
\[\text{both (A) and (B)}\]
123.
How can the following reaction be made to proceed in forward direction?
$$B{\left( {OH} \right)_3} + NaOH \rightleftharpoons NaB{O_2} + Na\left[ {B{{\left( {OH} \right)}_4}} \right] + {H_2}O$$
A
addition of borax
B
addition of $$cis{\text{ - 1, 2 - diol }}$$
C
addition of $$N{a_2}HP{O_4}$$
D
addition of $$trans{\text{ - 1, 2 - diol }}$$
Answer :
addition of $$cis{\text{ - 1, 2 - diol }}$$
124. Name of the synthetic radioactive element of group 16 having atomic number 116 is
A
Livermorium
B
Tennessine
C
Livernorium
D
Moscovium.
Answer :
Livermorium
125. Which of the following statements is not correct?
A
Oxygen molecule is paramagnetic with two unpaired electrons.
B
Sulphur shows maximum covalency of four.
C
Ozone can be easily detected by mercury.
D
Both sulphurous and sulphuric acid are dibasic in nature.
Answer :
Sulphur shows maximum covalency of four.
126. Which of the following halides is least stable and has doubtful existence?
A
$$C{l_4}$$
B
$$Ge{I_4}$$
C
$$Sn{I_4}$$
D
$$Pb{I_4}$$
Answer :
$$Pb{I_4}$$
127. The reason for not storing $$Xe{F_6}$$ in a glass or a quartz vessel is that
A
it forms an explosive having the formula $$Xe{O_2}{F_2}.$$
B
it forms an explosive having the formula $$XeO{F_4}.$$
C
it forms $$Xe{O_2}$$ which is explosive substance.
D
it forms $$Xe{O_6}^{4 - }$$ which is explosive in nature.
Answer :
it forms an explosive having the formula $$XeO{F_4}.$$
128. An aqueous solution of $$FeS{O_4},A{l_2}{\left( {S{O_4}} \right)_3}$$ and chrome alum is heated with excess of $$N{a_2}{O_2}$$ and filtered. The materials obtained are :
A
a colourless filtrate and a green residue
B
a yellow filtrate and a green residue
C
a yellow filtrate and a brown residue
D
a green filtrate and a brown residue
Answer :
a yellow filtrate and a brown residue
129. Which reaction represents the oxidizing behaviour of $${H_2}S{O_4}?$$
A
$$2PC{l_5} + {H_2}S{O_4} \to $$ $$2POC{l_3} + 2HCl + S{O_2}C{l_2}$$
B
$$2NaOH + {H_2}S{O_4} \to $$ $$N{a_2}S{O_4} + 2{H_2}O$$
C
$$NaCl + {H_2}S{O_4} \to NaHS{O_4} + HCl$$
D
$$2HI + {H_2}S{O_4} \to {I_2} + S{O_2} + 2{H_2}O$$
Answer :
$$2HI + {H_2}S{O_4} \to {I_2} + S{O_2} + 2{H_2}O$$
130. Which of the following statements about $${H_3}B{O_3}$$ is not correct?
A
It is a strong tribasic acid
B
It is prepared by acidifying an aqueous solution of borax
C
It has a layer structure in which planar $$B{O_3}$$ units are joined by hydrogen bonds
D
It does not act as proton donor but acts as a Lewis acid by accepting hydroxyl ion
Answer :
It is a strong tribasic acid