Properties of Dilute Base
The solution prepared by adding a comparatively smaller amount of base in a larger amount of water is called dilute base.
1. Litmus Test:
Take a small amount of sodium hydroxide solution in a test tube and then put a piece of red litmus paper in it. You will see the red litmus will turn a blue colour.
Again, take some NaOH solution in a test tube and put a blue litmus paper in the tube. The blue litmus will remain as it is, blue colour. This proves that basic solution only turns red litmus into a blue.
2. Feelings:
If you touch NaOH solution with your hand, it will feel slippery. Basic compounds are slippery in nature. However, contact with base is harmful to our skin.
Dilute Base in Reaction with Metallic Salts
Undergoing reaction with metallic salts like aluminium nitrate [Al(NO3)3], ferrous nitrate [Fe(NO3)2], ferric nitrate [Fe(NO3)3], zinc nitrate [Zn(N O3)2] dilute base produces the related metallic hydroxide. Mentionable, here we have only used nitrate salts. Apart from it, metallic chloride, metallic sulfate, metallic sulfate salts will give the same result. Let’s look at the following examples:
1.The reaction between dilute NaOH and Al(NO3)3:
If we take some Al(NO3)3 solution in a test tube and then add some drops of dilute NaOH solution in it, they produce aluminium hydroxide [Al(OH)3] and sodium nitrate (NaNO3). Where Al(OH)3 gathers as a white precipitate at the bottom of a test tube and sodium nitrate remains dissolved in the water and it does not add any colour to the water. The reaction is: 
2. The reaction between dilute NaOH and Fe(NO3)2:
Taking some ferrous nitrate Fe(NO3)2 solution in a test tube then add some drops of dilute NaOH solution in it, they produce ferrous hydroxide [Fe(OH)2] and sodium nitrate (NaNO3).
Where Fe(OH)2 appears as a green precipitate at the bottom of a test tube and sodium nitrate remains dissolved in the water and it does not add any colour to the water. The reaction is:
3. The reaction between dilute NaOH and Cu(NO3)2:
Taking some copper nitrate Cu(NO3)2solution in a test tube and add some drops of dilute NaOH solution in it, they produce copper hydroxide [Cu(OH)2] and sodium nitrate (NaNO3). Cu(OH)2 appears as a light blue precipitate at the bottom of test tube while sodium nitrate remains dissolved in the water and it does not add any colour to the water. The reaction is:
4. The reaction between Alkali (dilute NaOH) and Ammonium Salt:
Taking some ammonium chloride (NH4C1) in a container and add some alkali (NaOH) solution in it, they produce ammonia gas (NH3), sodium chloride (NaCl) and water (H2O). The reaction is : 
It is a characteristic reaction between ammonium salt and alkali. Alkali undergoes reaction with an ammonium salt and produces NH3 gas. Some examples are: 
