Chemistry Question Bank

The lead of the lead pencils melts at (AIIMS 2009) p-BLOCK (Group 13 - 14)

Boric acid is used in carrom boards for smooth gliding of pawns because:

What are X and Y in the reaction ? heat 3B H 6X 3[BH (X) ] [BH ] Y 12H + - + ® ¾¾¾® +

Graphite is a good conductor of electricity. Its electrical conductivity is due to the fact that (CPMT 2010)

When alumina is heated with carbon in nitrogen atmo- sphere, the products are:

Which of the statement is true for the above sequence of reactions?

Assertion: Silicones are hydrophobic in nature. Reason: Si–O–Si linkages are moisture sensitive. (AIIMS 2006)

BCl₃ does not exist as a dimer but BH₃ exists as B₂H₆ because

The main factor responsible for weak acidic nature of B—F bonds in BF₃ is:

Carbon and silicon belong to (IV) group. The maximum coordination number of carbon in commonly occurring compounds is 4, whereas that of silicon is 6. This is due to (AIPMT 1994)

Which one of the following is the correct statement ?

The power of halides of boron to act as Lewis acids decreases in the order:

Boron compounds behave as Lewis acids, because of their (AIPMT 1996)

Which of the following compounds is known as inor- ganic benzene?

NaBH₄ + I₂ ® X + Y + Z BF₃ + NaH 450 K ¾¾¾® X + P BF₃ + LiAlH₄ ® X + Q + R X, Y, Z, P, Q and R in the reactions are X Y Z P Q R (a) Na₄B₄O₇ NaI HI HF LiF AlF₃ (b) B₂H₆ NaI H₂ NaF LiF AlF₃ (c) B₂H₆ BH₃ NaI B₃N₃H₆ Al₂F₆…

In graphite, electrons are

Boron cannot form which one of the following anions? (a) BF⁻ (b) BH⁻

Which of the following is a false statement ?

Which of the following types of forces bind together the carbon atoms in diamond? (AIPMT 1992)

On hydroloysis, diborane produces

The structure of diborane (B₂H₆) contains :

Boric acid has a polymeric layer structure in which planar BO₃ units are joined by

In B₂H₆:

A type of zeolite used to convert alcohols directly into gasoline is

Borazole, B₃N₃H₆ is related to benzene as: