21.

Four successive members of the first-row transition elements are listed below with atomic numbers. Which one of them is expected to have the highest   value?

• Cr (Z =24)

• Mn(Z =25)

• Fe (Z = 26)

• Fe (Z = 26)

How many litres of water must be added to 1 L to an aqueous solution of HCl with a pH of 1 create an aqueous solution with PH of 2?

• 0.1 L

• 0.9 L 

• 2.0 L 

• 2.0 L 

Arrange the following compounds in order of decreasing acidity

• II>IV>I>III

• I>II>III>IV

• III>I>II>IV

• III>I>II>IV

A solution of (–) –1 – chloro –1 – phenylethane is toluene racemises slowly in the presence of a small amount of SbCl₅, due to the formation of

• carbanion

• Carbene

• Carbocation

• Carbocation

A compound with molecular mass 180 is acylated with CH3COCl to get a compound with molecular mass 390. The number of amino groups presents per molecule of the former compound is 

• 2

• 5

• 4

• 4

The order of stability of the following carbocations,

• III>II>I

• II> III>I

• I>II>III

• I>II>III

Synthesis of each molecule of glucose in photosynthesis involves

• 18 molecules of ATP

• 10 molecules of ATP

• 8 molecules of ATP

• 8 molecules of ATP

Compound (A), C₈H₉Br, gives a white precipitate when warmed with alcoholic AgNO₃. Oxidation of (A) gives a acid (B), C₈H₆O₄. (B) easily forms anhydride on heating. Identify the compound (A)

An organic compound A upon reacting with NH₃ gives B. On heating B gives C. C in presence of KOH reacts with Br₂ to give CH₃CH₂NH₂. A is

• CH₃COOH

• CH₃CH₂CH₂COOH

• 
• 

An unknown alcohol is treated with the “Lucas reagent” to determine whether the alcohol is primary, secondary or tertiary. Which alcohol reacts fastest and by what mechanism

• Secondary alcohol by S_N1

• Tertiary alcohol by S_N1

• Secondary alcohol by S_N2

• Secondary alcohol by S_N2