JEE Questions for Chemistry Class 11 P Block Elements Quiz 2 - MCQExams.com

Flint glass which is a mixture of silicates of potassium and lead (K₂O.Pb₂O.4SiO₂) is used for making optical instruments.

Agate is also known as silicon dioxide. Its formula is SiO₂.

In group 13 elements, electronegativity decreases from Boron to Aluminium and actually increases from alluminium and actually increases from aluminimum to thallium. This anamaly for the series- Ga, IN, Tl can be explained the increase in the effective nuclear charge (Z_eff) that results from poor shielding of the nuclear charge by the filled (n-1)d¹⁰ and (n-2)f¹⁴ subshells Consequently, although the actual nuclear charge increase by 32 as we go from in to Tl, screening by the filled 5d and 4f subshells is a so poor that Z_eff increase significantly from In to Tl. Thus the first ionization energy of thallium is actually greater than that of indium.

Aluminium hydroxide is amphoteric. Because it reacts with both acids and bases. Like any coventional base, the OH radical in Al(OH)₃ neutralizes H⁺ to make water and an aluminium salt. Al(OH)₃ solid will also react with excess OH^– to dissolve and form the complex ion [Al(OH)₄]^-.

Aluminium is considered an active metal. Its behaviour is deceptive because it reacts rapidly with the oxyagen in the air to form aluminium oxide (Al₂O₃) or alumina, which is tightly bound to the metal and exists as a dense coating (unlike the oxides of iron). This coating protects it from further reaction. So it is not reduces by chemical reactions.

Duralumin is an alloy of aluminium (94%), copper (4%) and magnesium (1%).

Small quantities of manganese and silicon may also be present. Duralumin is a low density alloy. It has a higher strength to weight ratio than pure aluminium.

Duralumin is used for aircraft construction.

Aluminium is too high in the electrochemical series (reactivity series) i.e

It is a stronger reducing agent than carbon and therefore it cannot be extracted from its ore using carbon reduction .

Boron halides are commonly refreed to as electron deficient a description that is reinforced by its exothermic reactivity toward Lecuis bases. Hence Boron halides behave as Lecuis acid.