[Maximum number: 2]

Urea, $\left(\mathrm{H}_{2} \mathrm{~N}\right)_{2} \mathrm{CO}$ , is excreted by mammals and can be used as a fertilizer.

(a)

Describe the bond formation when urea acts as a ligand in a transition metal complex ion.

[ 2 ]

[Maximum number: 1]

Ethyne, $\mathrm{C}_{2} \mathrm{H}_{2}$ , reacts with oxygen in welding torches.

(a)

Ethyne reacts with steam.

Two possible products are:

[ 1 ]

(i)

Product A contains a carbon-carbon double bond. State the type of reactions that compounds containing this bond are likely to undergo.

[ 1 ]

[Maximum number: 2]

Chlorine undergoes many reactions.

(a)

(i)

Write the equation for the reaction of chloroethane with a dilute aqueous solution of sodium hydroxide.

[ 1 ]

(ii)

Deduce the nucleophile for the reaction in d(iii).

[ 1 ]

[Maximum number: 3]

Chlorine undergoes many reactions.

(a)

(i)

Explain the mechanism of the reaction between chloroethane and aqueous sodium hydroxide, NaOH(aq), using curly arrows to represent the movement of electron pairs.

[ 3 ]

[Maximum number: 2]

Alkanes are commonly occurring organic compounds.

(a)

Chloroethane can be converted to ethanol. Identify the reagent and conditions necessary for this reaction to occur.

Reagent:
Conditions:

[ 2 ]

[Maximum number: 2]

Alkanes are commonly occurring organic compounds.

(a)

Chloroethane can be converted to ethanol. Identify the reagent and conditions necessary for this reaction to occur.

Reagent:
Conditions:

[ 2 ]

[Maximum number: 3]

Hydrogen cyanide, HCN , is a very toxic compound.

(a)

The cyanide ion reacts with iodomethane, $\mathrm{CH}_{3} \mathrm{I}$ .

[ 3 ]

(i)

Predict, giving a reason, whether this reaction will occur by an $\mathrm{S}_{\mathrm{N}} 1$ or $\mathrm{S}_{\mathrm{N}} 2$ mechanism.

[ 1 ]

(ii)

Explain how you might experimentally conclude whether the mechanism of this reaction is $\mathrm{S}_{\mathrm{N}} 1$ or $\mathrm{S}_{\mathrm{N}} 2$ .

[ 2 ]

[Maximum number: 2]

Halogenoalkanes are used as refrigerants and solvents.

(a)

Substance X undergoes nucleophilic substitution with a hydroxide nucleophile.

[ 2 ]

(i)

Describe the movement of electron pairs during the reaction using curly arrows.

[ 2 ]

[Maximum number: 1]

Cobalt forms the complex $\left[\mathrm{Co}\left(\mathrm{NH}_{3}\right)_{5} \mathrm{Cl}\right]^{2+}$ . Which statements are correct for this complex?
I. The cobalt ion acts as a Lewis acid.
II. The cobalt ion has an oxidation number of + II.
III. There are $90^{\circ}$ bond angles between the cobalt ion and the ligands.

I and II only

I and III only

II and III only

I, II and III

[Maximum number: 1]

Which species cannot act as a ligand?

$\mathrm{NH}_{4}{ }^{+}$

$\mathrm{H}_{2} \mathrm{O}$

$\mathrm{Cl}^{-}$

$\mathrm{OH}^{-}$