Which of the following will replace Br₂ from the aqueous solution having bromide ion?

• Cl₂

• I${}_3^{⊝}$

• I₂

• Cl^{${}^{⊝}$}

72.

If 2.0 g of a radioactive substance has half-life of 7 days, the half-life of 1 g sample is

• 7 days

• 14 days

• 28 days

• 35 days

According to the adsorption theory of catalysis the speed of the reaction increase because

• the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption

• in the process of adsorption, the activation energy of the molecules becomes large

• absorption produces heat which increases the speed of the reaction

• adsorption lowers the activation energy of the reaction

In the metallurgy of which of the following cupellation process is used? 

• Copper

• Silver

• Iron

• Aluminium

Cryolite is used in the electrolytic extration of aluminium

• to obtain more aluminium

• to decompose bauxite

• to protect anodes

• as a reducing agent

The brass is an alloy of

• gold and copper

• silver and zinc

• copper and zinc

• copper and aluminum

Which of the following is pseudo halogen?

• IF₇

• (CN)₂

• ICl${}_2^{-}$

• I${}_3^{-}$

Which element from group V gives most basic compound with hydrogen?

• Nitrogen

• Bismuth

• Arsenic

• Phosphorus

Point out in which of the following properties oxygen differs from the rest of the members of its family (Group-VIA)?

• High value of ionisation energies

• Oxidation states (2,4,6)

• Polymorphism

• Formation of hydrides

Which of the following properties increases on going down from F to I in group VII-A of the periodic table?

• Electronegativity

• Volatile nature

• Ionic radius

• Oxidising power