21.

Which of the following compounds is carbondum?

• Al₂O₃

• SiO₂

• SiC

• SnO₂

Which of the following statements is false ?

• CaOCl₂ gives OH^- Cl^- and OCl^- in aqueous solution

• Diamond and graphite are allotropes of carbon

• Bleaching action of Cl₂ in moist condition is not permanent

• Calomel is Hg₂Cl₂

The reaction of HBr with  in the presence of peroxide will give

• 

• 

• 

• CH₃CH₂CH₂CH₂Br

Which of the following will show geometrical isomerism?

• but-1-ene

• but-2-ene

• 2, 3-dichlorobutane

• ethene

What will be the IUPAC name of given compound?

• 2, 5-diethyl-4-methylhexane

• 3, 4, 6-trimethyloctane

• 2, 5, 6-trimethyloctane

• 3, 5-dimethyl-6-ethylheptane

A mixture of camphor and benzoic acid can be separated by :

• chemical method

• sublimation

• fractional distillation

• extraction with a solvent

Hardness of water is due to presence of salts of:

• Na⁺ and K⁺

• Ca²⁺ and Mg²⁺

• Ca²⁺ and K⁺

• Ca²⁺ and Na⁺

Which one of the following contain isopropyl group?

• 2, 2, 3, 3-tetramethylpentane

• 2-methylpentane

• 2, 2, 3-trimethylpentane

• 3, 3-dimethylpentane

Cr is member of 3d transition series of atomic number 24. What will be its electronic configuration ?

• 3d⁶4s²

• 3d⁵4s²

• 3d⁴4s²

• 3d⁵4s¹

What amount of Cl₂ gas liberated at anode, if 1 ampere current is passed for 30 minute from NaCl solution ?

• 0.66 mol

• 0.33 mol

• 0.66 g

• 0.33 g