Thermal decomposition method is used to purify

1)  Ti

2)  Ni

3)  Zr

4)  Cr

p-type silicon is formed by adding a minute amount of an element with :

1) three valence electrons
2) five valence electrons
3) four valence electrons
4) six valence electrons

Which of the following has maximum number of zero values appear in the curve plotted between ψ²  (probability of finding electron) versus radius?

1) 3p
2) 4d
3) 5p
4) 4f

The rate constant of a reaction depends on : 

1) the temperature of the system
2) the time of reaction
3) the extent of reaction
4) the initial concentration of the     reactants

The co-ordination number of a metal in co-ordination compounds is:

1) sum of primary and secondary   valencies
2) same as the oxidation number of the  central metal atom
3) same as primary valenecy
4) same as secondary valency

The pair of amphoteric hydroxides is:

1) Al(OH)₃ and LiOH
2) B(OH)₃ and Be(OH)₂
3) Be(OH)₂ and Zn(OH)₂
4) Be(OH)₂ and Mg(OH)₂

Which of the following compound contains intermolecular H-bonds?

1)  resorcinol

2)  ethanoic acid

3)  o-nitrophenol

4)  phenol

Which of the following fertilizers does not replenish nitrogen in the soil? :

1) CAN
2) Urea
3) Super phosphate lime.
4) Ammonium phosphate

X on treatment with sodium hydroxide followed by the addition of silver nitrate gives white precipitate at room temp, which are soluble in NH₄OH. X can be

1)  Vinyl chloride

2)  Benzyl chloride

3)  Ethyl bromide

4)  Chloro benzene

Which of the following statements is wrong about the following reaction? 

1) $$\displaystyle BBr_{3}$$ plays a role similar to the H in HI by forming a complex with the ether
2) The liberated $$\displaystyle Br^{\circleddash }$$ attacks Et, displacing $$\displaystyle PhOBBr_{2},$$ which is ultimately hydrolysed to give the products.
3) The products are $$\displaystyle PhOH+EtBr+H_{3}BO_{3}.$$
4) The products are $$\displaystyle PhBr+EtOH+H_{3}BO_{3}.$$