CBSE Questions for Class 11 Engineering Chemistry Some P-Block Elements Quiz 8 - MCQExams.com

In 3rd A group Tl shows +1 oxidation state while other member shows +3 oxidation state due to inert pair effect. The inert pair effect is the tendency of the electrons in the outermost atomic S orbital to remain unionized or unshared in compounds of post-transition metals.

So in $$Tl$$ only outer electron i.e $$np^{1}$$ participate in chemical bonding whereas the $$ns^{2}$$ do not participate in chemical bonding in a chemical reaction but other elements in that group do not show inert pair effect.

Hence option B is correct.

Germanium(II) hydrides, also called germylene hydrides, are a class of Group $$14$$ compounds consisting of low-valent germanium and a terminal hydride. They are also typically stabilized by an electron donor-acceptor interaction between the germanium atom and a large, bulky ligand. Germanium is the chemical compound with the formula $$GeH_4$$, and the germanium analogue of methane. It is the simplest germanium hydride and one of the most useful compounds of germanium.

Similarly $$GeH_6$$ is also one of the hydrides

A hydride is the anion of hydrogen, $$H^{ - }$$, more commonly, it is a compound in which one or more hydrogen centres have nucleophilic, reducing, or basic properties. In compounds that are regarded as hydrides, the hydrogen atom is bonded to a more electropositive element or group. Compounds containing hydrogen bonded to metals or metalloid may also be referred to as hydrides. Almost all of the elements form binary compounds with hydrogen, the exceptions being $$He, Ne, Ar, Kr, Pm, Os, Ir, Rn, Fr,$$ and $$Ra$$

Plumbane, $${ PbH }_{ 4 }$$, is a metal hydride and group 14 hydride composed of lead and hydrogen.

$$\left[ 1 \right] $$ Plumbane is not well characterized or well known, and it is thermodynamically unstable with respect to the loss of a hydrogen atom.

$$\left[ 2 \right] $$ Derivatives of plumbane include lead tetrafluoride, ($${ PbF }_{ 4 }$$), and tetraethyllead, $$\left( { \left( { CH }_{ 3 }{ CH }_{ 2 } \right)  }_{ 4 }Pb \right) $$

$$Al^{ 3+ }$$ aqueous acid $$\rightarrow { \left[ Al{ \left( { H }_{ 2 }O \right) }_{ 6 } \right] }^{ 3+ }$$.

$${ Al }^{ 3+ }$$ ions give a complex ion in which $${ Al }^{ 3+ }$$ ion form six coordinate covalent bonds with six $${ H }_{ 2 }O$$ molecules.

Hence, it shows $${ sp }^{ 3 }{ d }^{ 2 }$$ hybridisation.

(Due to availability of vacant $$3d$$-orbitals.)

$$Al=3{ s }^{ 2 }3{ p }^{ 1 }$$

$${ Al }^{ 3+ }=3{ s }^{ 0 }$$

Four electron pairs denoted by $$6{ H }_{ 2 }O$$ molecules.

Correct Option: $$D$$

Hint: The chemical formula of Borax is $$Na_2B_4O_7$$.

Explanation:

• When a solution of Borax reacts with a mineral acid such as $$HCl$$ orthoboric acid is formed.
  
  
• The reaction is as shown below;

$$Na_2B_4O_7+5H_2O+2HCl\rightarrow 4H_3BO_3+2NaCl$$

• Orthoboric acid is a weak, monobasic acid of boron.

1. It is not a tribasic acid. 

Option A is incorrect for $$H_3BO_3$$.

2. Aqueous solution, instead of donating the $$-OH$$ group it breaks the $$H-OH$$ bond of water and accepts the $$-OH$$ group from it leaving  in the solution hence it is mono basic acid.

• The common oxidation states exhibited by this family are $$+4$$ and $$+2$$.
• The tendency to show  $$+2$$ oxidation state increases in down the group.
• Due to the inert pair effect, down the group the tendency to form ions with $$+2$$ oxidation state increases from $$Ge$$ to $$Pb$$.
• The stability order is in increasing order of atomic number.