Q.1. Among the following alkaline earth metal halides, one which is covalent and soluble in organic solvents is: (2021)
(a) Magnesium chloride
(b) Beryllium chloride
(c) Calcium chloride
(d) Strontium chloride
BeCl2 is covalent and soluble in a organic solvent.
Q.2. The structures of beryllium chloride in solid state and vapour phase, are : (2021)
(a) Dimer and Linear, respectively.
(b) Chain in both.
(c) Chain and dimer, respectively.
(d) Linear in both.
The structures of beryllium chloride in the solid state and vapour phase, respectively are chain and dimeric.
In vapour phase at above 900∘C. BeCl2 is monomeric having a linear structure Cl−Be−Cl. The bonding in BeCl2 is covalent and Be atom accommodates 2 + 2 = 4 electrons in the two sp− hybrid orbitals. Below 900∘C, beryllium chloride in vapour phase exists as a mixture of monomer BeCl2 and Be2Cl4.
Q.3. The following metal ion activates many enzymes, participates in the oxidation of glucose to produce ATP and with Na, is responsible for the transmission of nerve signals. (2021)
Q.4. Which of the following is an amphoteric hydroxide? (2019)
Be(OH)2 is amphoteric in nature, since it can react with both acid and base
Be(OH)2 + 2HCl → BeCl2 + 2H2O
Be(OH)2 + 2NaOH → Na2 [Be(OH)4]
Q.5. Enzymes that utilize ATP in phosphate transfer require an alkaline earth metal (M) as the co-factor. M is : (2019)
All enzymes that utilize ATP in phosphate transfer require magnesium(Mg) as the co-factor.
Q.6. Which of the following oxides is most acidic in nature? (2018)
In metals moving down the group metallic character increases, So basic nature increases down the group. Hence, most acidic will be BeO.
Q.7. Among CaH2, BeH2, BaH2, the order of ionic character is (2018)
(a) BeH2 < CaH2 < BaH2
(b) CaH2 < BeH2 < BaH2
(c) BeH2 < BaH2 < CaH2
(d) BaH2 < BeH2 < CaH2
BeH2 < CaH2 < BaH2
Smaller the size of cation, more will be its polarising power. Hence BeH2 will be least ionic.
Q.8. Ionic mobility of which of the following alkali metalions is lowest when aqueous solution of their saltsare put under an electric field ? (2017)
Q.9. Which of the following statement is false ? (2016)
(a) Mg2+ ions are important in the green parts of plants.
(b) Mg2+ ions from a complex with ATP.
(c) Ca2+ ions are important in blood clotting.
(d) Ca2+ ions are not important in maintaining the regular beating of the heart.
Ca+2 ions are important in blood clotting and are also important in maintaining the regular beating of the heart.
Q.10. The function of 'sodium pump' is a biological process operating in each and every cell of all animal. Which of the following biologically important ions is also a constituent of this pump? (2015)
The sodium pump is also known as a sodium Potassium pump. This pump is important contributor to action potential produced by nerve cells. The process of moving sodium potassium ions across the cell membranes is active transport process involving the hydrolysis of ATP to provide the necessary energy.
Q.11. Solubility of the alkaline earth‘s metal sulphates in water decreases in the sequence : (2015)
(a) Ba > Mg > Sr > Ca
(b) Mg > Ca > Sr > Ba
(c) Ca > Sr > Ba > Mg
(d) Sr > Ca > Mg > Ba
Mg > Ca > Sr > Ba.
The solubility of sulphates decreases on moving down the group. The values of solubility products which decrease gradually also explain the decrease in solubility on moving down the group.