IB Chemistry HL S2.2 practice question

Paper 2Medium6 marks

Figure 1 shows reference bond angles for methane, ammonia and water. Each central atom has four electron domains.

(a)

Use Figure 1 to state the bond angle in water and compare the bond angles in ammonia and water.

[2]

(b)

Explain the difference between the bond angles in ammonia and water in terms of the electron domains around their central atoms.

[2]

(c)

Ammonia reacts with a hydrogen ion to form an ammonium ion:

\ce{NH3 + H+ -> NH4+}

Identify the atom that donates the electron pair to $\ce{H+}$ and explain why the N–H bond formed is a coordination bond.

[2]