131.
Two metals $$X$$ and $$Y$$ belong to the second group of periodic table. $$X$$ forms insoluble oxide but soluble sulphate. $$Y$$ forms a soluble oxide but insoluble sulphate. Hydroxide of metal $$X$$ is soluble in $$NaOH$$ while that of metal $$Y$$ is insoluble in $$NaOH.$$ What are metals $$X$$ and $$Y?$$
132.
Calcium imide on hydrolysis gives gas $$(B)$$ which on oxidation by bleaching powder gives gas $$(C).$$ Gas $$(C)$$ on reaction with magnesium give compound $$(D)$$ which on hydrolysis gives again gas $$(B).$$ Identify $$(B), (C)$$ and $$(D).$$
A
$$N{H_3},{N_2},M{g_3}{N_2}$$
B
$${N_2},N{H_3},MgNH$$
C
$${N_2},{N_2}{O_5},Mg{\left( {N{O_3}} \right)_2}$$
Alkali and alkaline earth metals react with water to produce hydrogen gas and metal hydroxide. This is due to their high electropositive character.
$$Mg + 2{H_2}O \to Mg{\left( {OH} \right)_2} + {H_2}$$
135.
Which of the following are found in biological fluids $$N{a^ + },M{g^{2 + }},C{a^{2 + }},{K^ + },S{r^{2 + }},L{i^ + }$$ and $$B{a^{2 + }}?$$
A
$$M{g^{2 + }},C{a^{2 + }},\,{\text{and}}\,S{r^{2 + }}$$
B
$$N{a^{2 + }}\,{\text{and}}\,{K^ + }$$
C
$$N{a^ + },{K^ + },M{g^{2 + }}\,{\text{and}}\,C{a^{2 + }}$$
137.
If $$NaOH$$ is added to an aqueous solution of $$Z{n^{2 + }}ions,$$ a white precipitate appears and on adding excess $$NaOH,$$ the precipitate dissolves. In this solution zinc exists in the :
138.
Halides of alkaline earth metals form hydrates such as $$MgC{l_2} \cdot 6{H_2}O,CaC{l_2} \cdot 6{H_2}O,$$ $$BaC{l_2} \cdot 2{H_2}O$$ and $$SrC{l_2} \cdot 2{H_2}O.$$ This shows that halides of group 2 elements
$$Na, K$$ and $$Ca$$ decompose water by evolving hydrogen gas. However $$Be$$ does not react with water even when red hot. Its protective oxide layer survives even at high temperature.