141. Which of the carbonates given below is unstable in air and is kept in $$C{O_2}$$ atmosphere to avoid decomposition?
A
$$BeC{O_3}$$
B
$$MgC{O_3}$$
C
$$CaC{O_3}$$
D
$$BaC{O_3}$$
Answer :
$$BeC{O_3}$$
142. In crystals which one of the following ionic compounds would you expect maximum distance between centres of cations and anions?
A
$$LiF$$
B
$$CsF$$
C
$$CsI$$
D
$$LiI$$
Answer :
$$CsI$$
143. Beryllium shows diagonal relationship with aluminium. Which of the following similarity is incorrect?
A
$$B{e_2}C$$ like $$A{l_4}{C_3}$$ yields methane on hydrolysis.
B
$$Be$$ like $$Al$$ is rendered passive by $$HN{O_3}.$$
C
$$Be{\left( {OH} \right)_2}$$ like $$Al{\left( {OH} \right)_3}$$ is basic.
D
$$Be$$ forms beryllates and $$Al$$ forms aluminates.
Answer :
$$Be{\left( {OH} \right)_2}$$ like $$Al{\left( {OH} \right)_3}$$ is basic.
144. A solid compound $$'X'$$ on heating gives $$C{O_2}$$ gas and a residue. The residue mixed with water forms $$'Y'.$$ On passing an excess of $$C{O_2}$$ through $$'Y'$$ in water, a clear solution $$'Z',$$ is obtained. On boiling $$'Z',$$ compound $$'X'$$ is reformed. The compound $$'X'$$ is
A
$$Ca{\left( {HC{O_3}} \right)_2}$$
B
$$CaC{O_3}$$
C
$$N{a_2}C{O_3}$$
D
$${K_2}C{O_3}$$
Answer :
$$CaC{O_3}$$
145. The formula of soda ash is
A
$$N{a_2}C{O_3} \cdot 10{H_2}O$$
B
$$N{a_2}C{O_3} \cdot 2{H_2}O$$
C
$$N{a_2}C{O_3} \cdot {H_2}O$$
D
$$N{a_2}C{O_3}$$
Answer :
$$N{a_2}C{O_3}$$
146. Which is the correct sequence of solubility of carbonates of alkaline earth metals?
A
$$BaC{O_3} > SrC{O_3} > CaC{O_3} > MgC{O_3}$$
B
$$MgC{O_3} > CaC{O_3} > SrC{O_3} > BaC{O_3}$$
C
$$CaC{O_3} > BaC{O_3} > SrC{O_3} > MgC{O_3}$$
D
$$BaC{O_3} > CaC{O_3} > SrC{O_3} > MgC{O_3}$$
Answer :
$$MgC{O_3} > CaC{O_3} > SrC{O_3} > BaC{O_3}$$
147. The pair of compounds which cannot exist together in solution is:
A
$$NaHC{O_3}\,\,{\text{and}}\,NaOH$$
B
$$N{a_2}C{O_3}\,\,{\text{and}}\,NaHC{O_3}$$
C
$$N{a_2}C{O_3}\,\,\operatorname{and} \,NaOH$$
D
$$NaHC{O_3}\,{\text{and}}\,NaCl$$
Answer :
$$NaHC{O_3}\,\,{\text{and}}\,NaOH$$
148. Which of the following is not the point of difference between $$Be$$ and other alkaline earth metals?
A
It has a tendency to form covalent bonds.
B
It dissolves in alkalies with evolution of hydrogen.
C
Its oxides and hydroxides are amphoteric.
D
Its carbide gives acetylene on hydrolysis.
Answer :
Its carbide gives acetylene on hydrolysis.
149. The ionisation energy of alkali metals decreases from $$Li$$ to $$Cs$$ because
A
the atomic size increases from $$Li$$ to $$Cs$$
B
the distance between nucleus and outermost orbital decreases from $$Li$$ to $$Cs$$
C
electropositive character decreases down the group
D
melting point decreases from $$Li$$ to $$Cs$$
Answer :
the atomic size increases from $$Li$$ to $$Cs$$
150. A solution of sodium metal in liquid ammonia is strongly reducing due to the presence of
A
sodium atoms
B
sodium hydride
C
sodium amide
D
solvated electrons
Answer :
solvated electrons