(NH4)2MoO4 is used for the detection of__________

(NH₄)₂MoO₄ is used for the detection of phosphorous.

Explanation

(NH₄)₂MoO₄   is the chemical formula of the compound Ammonium orthomolybdate. The compound is a white solid that is prepared by treating molybdenum trioxide with aqueous ammonia.

Detection of phosphorous

The organic compound Ammonium orthomolybdate is treated with sodium peroxide(Na₂O₂). Phosphorus gets converted to sodium phosphate.

• The aqueous extract is heated with concentrated nitric acid (HNO₃) and ammonium molybdate{ (NH₄)₂MO_4 ^)}.
• A canary yellow precipitate of ammonium phosphomolybdate is collected.
• This yellow precipitate formed shows that Phosphorus is present in the organic compound.

Reaction that take place during the process

• In the first step, the reaction takes place as follows

Na₃PO₄+3HNO₃⟶H₃PO₄+3NaNO₃

• In the second step, the reaction takes place as follows

H₃PO₄+12(NH₄)₂MoO₄+21HNO₃⟶(NH₄)3PO4⋅12MoO₃+ 21NH₄NO₃+12N₂O

(NH₄)3PO4⋅12MoO₃ is the yellow precipitate formed.