To separate sand, NH₄Cl, and NaCl, you can use sublimation to isolate NH₄Cl, followed by dissolving the remaining mixture in water, filtering out the sand, and then evaporating the solution to recover NaCl. 

1. • Sublimation of NH₄Cl
   • Heat the mixture of sand, NH₄Cl, and NaCl in a china dish covered with a funnel (plugged with cotton). 
   • NH₄Cl will sublime (transform directly from solid to gas) and condense on the cooler surface of the funnel, leaving behind a mixture of sand and NaCl. 
   • Collect the NH₄Cl from the funnel walls. 

2.  Dissolving and Filtering:

   • Add water to the remaining mixture of sand and NaCl. 
   • NaCl will dissolve in water, while sand will remain undissolved. 
   • Filter the mixture to separate the sand from the NaCl solution. 

3. 3. Evaporating the NaCl Solution:

   • Evaporate the water from the NaCl solution, leaving behind solid NaCl crystals.