How to Identify Sodium Chloride (NaCl) and Sodium Bromide (NaBr)

There are tests to identify the presence of chloride ion and bromide ions in compounds. In both compounds, sodium ion is common. So we have to find an experiment which give different results with same reagent. In this tutorial, we are going to present you several inorganic qualitative analysis tests which can be used to identify chloride ion and bromide ion.

Both NaCl and NaBr are strong electrolytes. Therefore, aqueous sodium chloride (NaCl) and sodium bromide (NaBr) which gives bromide and chloride ions respectively to the water .

Both NaCl and NaBr are soluble in water their aqueous solutions are colorless. So we cannot identify chloride ion from their colors of solutions.

Identify chloride ion and bromide ion

There are several test, which gives different results (such as different colors, forming precipitates, emissions of gases etc when we treat several reagents to chloride and bromide ion.

Method 1: identify aqueous NaCl from aqueous KCl from aqueous silver nitrate

We use aqueous silver nitrate (AgNO_3(aq)) solution to identify chloride ion and bromide ion and we have learned this as an experiment above in this tutorial.

AgNO_3(aq) + NaCl_(aq) → AgCl_(s) + NaNO_3(aq)

AgNO_3(aq) + NaBr_(aq) → AgBr_(s) + NaNO_3(aq)

With silver nitrate, NaCl and NaBr gives AgCl and AgBr precipitates respectively.
AgCl is not soluble in water and form a white color precipitate
AgBr is a pale yellow color insoluble precipitate in water.

Due to color difference of two precipitates in two solutions, you can identify in which solution NaCl was.

Method 2: Testing sodium chloride and sodium bromide using lead nitrate solution

As silver nitrate solution, lead(II) nitrate ( Pb(NO₃)_2(aq) ) solution is used to identify sodium chloride and sodium bromide and we have learned this as an experiment above in tests for chloride ion.

Pb(NO₃)_2(aq) + NaCl_(aq) → PbCl_2(s) + NaNO_3(aq)

Pb(NO₃)_2(aq) + NaBr_(aq) → PbBr_2(s) + NaNO_3(aq)

With lead(II) nitrate, NaCl and NaBr gives PbCl₂ and PbBr₂ precipitates respectively.
Lead(II) chloride ( PbCl₂ ) is not soluble in water and form a white color precipitate
Lead(II) bromide ( PbBr₂) is a cream color insoluble precipitate in water.

Due to color difference of Lead(II) chloride and Lead(II) bromide precipitates formed in two solutions, you can identify in which solution NaCl was.

Method 3: Sodium chloride and sodium bromide reactions with concentrated sulfuric acid

Add concentrated sulfuric acid to aqueous NaCl and heat the solution HCl vapor is produced.
Add concentrated sulfuric acid to aqueous NaBr and heat the solution. You will see brown color bromine vapor is produced.

Explanation

HCl vapor is stable to heat and does not decomposes to hydrogen and chlorine gas.
But, hydrogen bromide (HBr) vapor is not stable to heat and decomposes to hydrogen and bromine vapor. That's why you see a brown color vapor is produced in NaBr solution.

Testing solid NaCl and solid NaBr

So far, we discussed how aqueous sodium chloride is identified from aqueous sodium bromide. Then how do I identify solid sodium chloride and sodium bromide.

Both solid compounds are white. You can do an experiment which was done to identify aqueous sodium chloride and aqueous sodium bromide.
What are the tests for chloride ion which are used to identify from nitrate ion? If you have to identify sodium chloride and sodium nitrate, you can add concentrated sulfuric acid.

Questions asked by students

Ask your question and find the answer free.

What is the aqueous nabr color?

It is a colorless solution. Usually most aqueous solutions of sodium salts are colorless.