21.

The reaction of  with HBr gives predominantly

• 

• 

• 

• 

An organic compound with molecular formula C₆H₁₂ upon ozonolysis give only acetone as the product. The compound is

• 2,3-dimethyl-1-butene

• 3-hexane

• 2-hexene

• 2,3-dimethyl-2-butene

Acyclic stereoisomer having the molecular formula C₄H₇Cl are classified and tabulated. Find out the correct set of numbers

• Geometrical	optical
  6	2

• Geometrical	optical
  4	2

• Geometrical	optical
  6	0

• Geometrical	optical
  6	0

Which one of the following carbanions is the least stable?

• CH₃CH₂^-

• CH₃^-

• (CH₃)₃C^-

• HC≡C^-

Which of the following is used as an oxidiser in rocket propellants?

• Ammonium perchlorate

• Alcohol

• Acrylic rubber

• Polyurethane

A solid compound contains X, Y and Z atoms in a cubic lattice with X atom occupying the comers. Y atoms in the body centred positions and Z atoms at the centres of faces of the unit cell. What is the empirical formula of the compound?

• XYZ

• X₂Y₂Z₃

• XYZ₃

• XY₂Z₃

KCl crystallises in the same type of lattice as does NaCl. Given that r_Na⁺/ r_Cl^-= 0.55 and r_K⁺/r_Cl^-= =0.74. Calculate the ratio of the side of the unit cell for KCl to that of NaCl. 

• 1.123

• 0.0891

• 1.414

• 0.414

The element evolving two different gases on reaction with conc sulphuric acid is

• P

• C

• Hg

• S

Which one of the following reactions will occur on heating AgNO₃ above its melting point?

• 2AgNO₃ → 2Ag + 2NO₂ + O₂

• 2AgNO₃ → 2Ag + N₂ + 3O₂

• 2AgNO₃ → 2AgNO₂ + O₂

• 2AgNO₃ → 2Ag + 2NO + 2O₂

Pick out the correct statements from the following

1.Cobalt (III) is more stable in octahedral complexes.

2. Zinc forms coloured ions or complexes.

3. Most of the d-block elements and their compounds are ferromagnetic.

4. Osmium shows (VIII) oxidation state.

5. Cobalt (II) is more stable in octahedral complex.

• 1 and 2

• 1 and 3

• 2 and 4

• 1 and 4