In the ammonium chloride experiment—

1. the temperature of water decreases as more $\mathrm{NH_4Cl}$ is dissolved
2. dissolution of $\mathrm{NH_4Cl}$ in water is an endothermic process
3. the experiment requires a thermometer, beaker, balance and glass rod

• ai and ii
• bii and iii
• ci and iii
• di, ii and iii