15 Facts About H2SO3+Ag3PO4: How This Combination Works

The aim of a chemical reaction is the formation of distinct stable products. Let us learn how this reaction works as an example.

H2SO3 is a weaker acid than sulphuric acid with a pH of 5.1,existing as an aqueous solution of sulphuric acid. Ag3PO4 is dark yellow chemical compound, insoluble in water and a decent photocatalyst due to its sensitivity towards light in reactions like photochemical splitting of water. It has a density of 6.370 g/cm3.

This insightful article will dive into various aspects of the reaction of the acid and phosphate salt, along with their properties.

What is the product of H2SO3 and Ag3PO4?

H2SO3 and Ag3PO4 are reacted to form silver sulphite and phosphoric acid respectively. The reaction occurs as,

2Ag3PO4 + 3H2SO3 3Ag2SO3 + 2H3PO4

What type of reaction is H2SO3 + Ag3PO4?

The reaction of H2SO3 and Ag3PO4 is a displacement reaction that is advised to perform in a dark environment.

How to balance H2SO3 + Ag3PO4?

H2SO3 and Ag3PO4 reaction has the following steps for proper stoichiometric balance:

  • Ag3PO4 + H2SO3 Ag2SO3 + H3PO4
  • To equal the number of atoms of Ag in both sides, multiply Ag on the left side with 2 and the right side with 3. This makes both sides having 6 atoms of Ag.
  • 2Ag3PO4 + 3H2SO3 3Ag2SO3 + 2H3PO4
  • As both ways must be equal in atoms, in terms of stoichiometry, multiply H2SO3 with 3 in the left and H­3PO4 with 2 in the right to equal the atoms of Hydrogen.
  • 2Ag3PO4 + 3H2SO3 3Ag2SO3 + 2H3PO4

H2SO3 + Ag3PO4 Titration

The titration of H2SO3 and Ag3PO4 will yield noticeable results.

Apparatus

  • Graduated burette
  • Conical flask
  • Volumetric flask
  • Burette stands
  • Sample beakers

Titre and Titrant

  • H2SO3 is used as the titrant, the substance that is to be measured
  • Ag3PO4 is the titre, its concentration remaining unknown.

Procedure 

  • The washed burette is filled with the sulphurous acid and clamped to the stand.  
  • Specific amount of the Ag3PO4 solution is added to the conical flask.
  • In the conical flask, drops of methyl orange indicator added as contents.
  • As the titration procedure begins, drops of the acid falls inside the flask.
  • At the equivalence point (may fluctuate in this reaction), equal moles of acid have reacted with equal moles of base, indicating end of the reaction.
  • A noticeable colour change may be observed with an indistinct solution soon followed.
  • The estimation of the salt is done by the formula:
  • VAg3PO4 SAg3PO4 = VH2SO43 SH2SO3
Titra ch
Titration Setup

H2SO3 + Ag3PO4 Net Ionic Equation

In the H2SO3 and Ag3PO4 reaction, the ionic equation follows the scheme:

6Ag+(aq) + 2PO43-(aq) + 6H+(aq) + 3SO32-(aq) 6Ag+(aq) + 3SO32-(aq) + 6H+(aq) + 2PO43-(aq)

H2SO3 + Ag3PO4 Conjugate Pairs

As an instance of conjugate pairs in the reaction,

  • The conjugate base of H2SO3 = HSO3
  • The conjugate base of H3PO4 = H2PO4

H2SO3 + Ag3PO4 Intermolecular Forces

  • H2SO3 is involved in hydrogen bonding due to the hydrogen present.
  • The solubility product of 8.89 x 10-17 is a proof of the water-insolubility of Silver Phosphate.
  • There exist weak Van der Waals’ forces between the atoms in silver phosphate.          

H2SO3 + Ag3PO4 Reaction Enthalpy

H2SO3 and Ag3PO4 reaction Enthalpy is – 4.2 kJ/mol. The enthalpy information goes as follows:

  • Enthalpy of Formation of Ag3PO4 = -1005 kJ/mol
  • Enthalpy of Formation of H2SO3 = -655.5 kJ/mol
  • Enthalpy of Formation of Ag2SO3 = -490.7 kJ/mol
  • Enthalpy of Formation of H3PO4 = -1254.3 kJ/mol
  • Reaction Enthalpy of above reaction= (-(3 x 490.7) – (2 x 1254.3)) – (-(2 x 1005) – (655.5 x 3))= (-1472.1 -2508.6) + (2010 + 1966.5) = -4.2 kJ/mol

Is H2SO3 + Ag3PO4 a Buffer Solution?

H2SO3 and Ag3PO4 do not form a strong buffer solution as the phosphate salt formed itself is not that stable and the acid cannot be a part of buffer.

Is H2SO3 + Ag3PO4 a Complete Reaction?

H2SO3 and Ag3PO4 reaction is a complete reaction with the requirement of an equilibrium as the reaction conditions should be strictly maintained.

Is H2SO3 + Ag3PO4 an Exothermic Reaction?

The H2SO3 and Ag3PO4 reaction is exothermic in nature with a small amount of energy being released.

Is H2SO3 + Ag3PO4 a Redox Reaction?

The reaction of H2SO3 and Ag3PO4 is not an actual redox reaction.

Is H2SO3 + Ag3PO4 a Precipitation Reaction?

H2SO3 and Ag3PO4 is not a precipitation reaction as the residue is highly unstable and may exist more in solution phase.

Is H2SO3 + Ag3PO4 a Reversible Reaction?

H2SO3 and Ag3PO4 reaction is not reversible in nature as the reaction proceeds to give other products when we change certain conditions.

Is H2SO3 + Ag3PO4 a Displacement Reaction?

The reaction of H2SO3 and Ag3PO4 is a double displacement reaction as the pair of ionic species gets interchanged in the product side.

  • Silver gets displaced by Hydrogen to form Ag2SO3
  • The phosphate species combines with hydrogen to give phosphoric acid.

Conclusion

Ag3PO4 is an important analytical reagent due to its precipitation properties but other derivatives are found to be fairly unstable. The titration described is not the best example of acid-base titration.