17 Facts on HCl + Na2S2O3: What, How To Balance & FAQs

HCl and Na₂S₂O₃ are the chemical names of hydrochloric acid and sodium thiosulfate. Here, we are discussing the chemical reaction within HCl and Na₂S₂O₃ compounds.

Hydrochloric acid is a strong acid composed of two elements i.e. hydrogen atom and chlorine atom. Sodium thiosulphate is an inorganic salt and is composed of mainly three elements i.e. 2 sodium atoms, 2 sulfur atoms, and 3 oxygen atoms.

In this article, we learn about the balanced equation, product, intermolecular forces, titration, enthalpy, net ionic equation, and many more facts with some FAQs on HCl + Na₂S₂O₃ chemical reaction.

What is the product of HCl and Na₂S₂O₃?

The product of HCl + Na₂S₂O₃ is sodium chloride (NaCl), water (H₂O), sulfur dioxide gas (SO₂), and sulfur (S) metal.

 Na₂​S₂​O₃ ​+ 2 HCl → 2 NaCl + H_2​O + SO₂ ​+ S

What type of reaction is HCl + Na₂S₂O₃?

The HCl + Na₂S₂O₃ is a disproportionate or dismutation reaction.

How to balance HCl + Na₂S₂O₃?

The HCl + Na₂S₂O₃ chemical reaction is balanced with the help of the following steps:

• The unbalanced reaction of HCl + Na₂S₂O₃ is given below:
• Na₂​S₂​O₃ ​+ HCl → NaCl + H_2​O + SO₂ ​+ S
• We have to multiply HCl on the left-hand side by 2, so we get.
• Na₂​S₂​O₃ ​+ 2 HCl → NaCl + H_2​O + SO₂ ​+ S
• Later we have to multiply Na2S2O3 on the right-hand side by 2, and we get.
• Na₂​S₂​O₃ ​+ 2 HCl → 2 NaCl + H_2​O + SO₂ ​+ S

HCl + Na₂S₂O₃ titration

The HCl + Na₂S₂O₃ reaction titration experiment is done to determine the rate of reaction by applying different concentrations of Na₂S₂O₃ treated with HCl.

Apparatus:

• 5 – 100 ml beakers
• 2 – 50 or 100 ml Graduated cylinders.
• 5 – 10 ml Graduated cylinders
• Permanent marker
• Lightbox or overhead projector
• Timer or stopwatch
• Stirring rods

Chemicals:

• 25 ml, 2 molars, Hydrochloric acid solution
• 150 ml, 0.15 molar, Sodium thiosulfate solution.
• Deionized or distilled water

Procedure:

• Label the entire five 100 ml beakers as 1 to 5 and clean the bottom of every beaker.
• Make a large “X” at the bottom of the beaker and place it on the stage of the lightbox or projector, so the X can be visible.
• Using a separate graduated cylinder, add the 0.15M Na₂S₂O₃ solutions in each of the five beakers as 1 – 50 ml, 2 – 40 ml, 3 – 30 ml, 4 – 20 ml, and 5 – 10 ml.
• Later add the distilled water in the same five beakers 1 – 0 ml, 2 – 10 ml, 3 – 20 ml, 4 – 30 ml, and 5 – 40 ml.
• Now, evaluate the Na₂S₂O₃ final concentration in each beaker from 1 to 5.
• Note the values of volume of Na₂S₂O₃ in a beaker, concentration of Na₂S₂O₃, distilled water volume, reaction time in seconds, and 1/reaction time i.e. reaction rate.
• Take 5 ml of 2 M HCl solution in each five 10 ml graduated cylinders.
• Add the 5 ml HCl solution in each of the 5 beakers containing Na₂S₂O₃ and distilled water solution, stir it with a stirring rod and immediately start the stopwatch.
• Stop the timer if the “X” on the beaker is not visible. Note the reaction time (sec) and repeat the same procedure with 2 to 5 beakers.
• Calculate the reaction rate for each trial and plot two separate graphs against concentration Vs reaction time and concentration Vs reaction rate.

HCl + Na₂S₂O₃ net ionic equation

• The net ionic equation for HCl + Na₂S₂O₃ chemical reaction is.
• 2Na⁺ + S₂O₃^– + 2H⁺ + 2Cl^– → 2Na⁺ + 2Cl^– + H₂O + SO₂ + S
• Cancel the same moieties on both sides we get.
• S₂O₃^– + 2H⁺ → H₂O + SO₂ + S

HCl + Na₂S₂O₃ conjugate pairs

HCl + Na₂S₂O₃ is a conjugate pair as HCl donates its proton and acts as conjugate acid, while Na₂S₂O₃ accepts a proton and forms NaCl thus acting as a conjugate base.

HCl and Na₂S₂O₃ intermolecular forces

The intermolecular forces shown by HCl and Na₂S₂O₃ are,

• HCl = dipole-dipole and London dispersion force.
• Na₂S₂O₃ = ion-dipole intermolecular force.

HCl + Na₂S₂O₃ reaction enthalpy

• The reaction enthalpy of the HCl + Na₂S₂O₃ reaction is -338.916 kJ/mol.
• Enthalpy of HCl is = −92.3 kJ/mol
• Enthalpy of Na₂S₂O₃ is = −586.2kJ/mol
• Enthalpy of NaCl is = -821.98 kJ/mol
• Enthalpy of H₂O is = -241,826 kJ/mol
• Enthalpy of SO₂ is = −296.81kJ/mol
• Enthalpy of S is = −395. 8kJ/mol
• Reaction enthalpy (∆H) of HCl + Na₂S₂O₃ = Enthalpy of product – enthalpy of reactant
• (∆H) of HCl + Na₂S₂O₃ = -1017.416 kJ/mol – (-678.5) kJ/mol
• (∆H) of HCl + Na₂S₂O₃ = -338.916 kJ/mol

Is HCl + Na₂S₂O₃ a buffer solution?

HCl + Na₂S₂O₃ is not a buffer solution, because the buffer solution is only formed between weak acid and weak base. HCl is a strong acid and Na₂S₂O₃ is a salt.

Is HCl + Na₂S₂O₃ a complete reaction?

HCl + Na₂S₂O₃ is not a complete reaction as it is not a reversible reaction and cannot achieve equilibrium.

Is HCl + Na₂S₂O₃ an exothermic or endothermic reaction?

HCl + Na₂S₂O₃ is an exothermic reaction because it has the negative value of enthalpy of formation. The HCl shows exothermic and Na₂S₂O₃ shows endothermic reaction as it is a salt.

Is HCl + Na₂S₂O₃ a redox reaction?

HCl + Na₂S₂O₃ is a redox reaction because the oxidation number of sulfur gets changed in the reactant and product. The oxidation number of the S atom in Na₂S₂O₃ is +2, in SO₂ is +4, and in sulfur, metal is zero. This is a form of disproportionate reaction.

Is HCl + Na₂S₂O₃ a precipitation reaction?

HCl + Na₂S₂O₃ is a precipitation reaction because the sulfur metal gets precipitated as a product in the reaction.

Is HCl + Na₂S₂O₃ reversible or irreversible reaction?

The HCl + Na₂S₂O₃ is an irreversible reaction because in this reaction the product cannot give back the reactants.

Is HCl + Na₂S₂O₃ displacement reaction?

HCl + Na₂S₂O₃ is a double displacement reaction and not a single displacement reaction. In this reaction, the atoms get exchanged and none of the atoms get displaced with other higher reactive atoms.

How to balance Na₂S₂O₃ + KMnO₄ + HCl = Na₂SO₄ + MnCl₂ + KCl + H₂O?

The steps to the balanced chemical equation of the Na₂S₂O₃ + KMnO₄ + HCl reaction are given below.

• Add 5 on LHS and RHS to make the balanced Na atoms we get.
• 5Na₂S₂O₃ + KMnO₄ + HCl → 5Na₂SO₄ + MnCl₂ + KCl + H₂O
• Then add 2 on LHS and RHS to balance the K, Mn, and Cl atoms we get.
• 5Na₂S₂O₃ + 2KMnO₄ + HCl → 5Na₂SO₄ + 2MnCl₂ + 2KCl + H₂O
• Finally, add 6 before HCl and 3 before H2O to balance all atoms of the equation we get.
• 5Na₂SO₃ + 2KMnO₄ + 6HCl → 5Na₂SO₄ + 2MnCl₂ + 2KCl + 3H₂O

How to balance K₂Cr₂O₇ + Na₂S₂O₃ + HCl = KCl + Na₂SO₄ + CrCl₃ + H₂O?

The balanced chemical equation of the K₂Cr₂O7 + Na₂S₂O₃ + HCl reaction is given below.

• Add 3 on LHS and RHS to balance the Na atoms on both sides we get.
• K₂Cr₂O₇ + 3Na₂S₂O₃ + HCl → KCl + 3Na₂SO₄ + CrCl₃ + H₂O
• Then add 2 on RHS before KCl and CrCl₃ and 8 on LHS before HCl we get.
• K₂Cr₂O₇ + 3Na₂S₂O₃ + 8HCl → 2KCl + 3Na₂SO₄ + 2CrCl₃ + H₂O
• Finally, add 4 before H₂O to balance the whole equation we get.
• K₂Cr₂O₇ + 3Na₂SO₃ + 8HCl → 2KCl + 3Na₂SO₄ + 2CrCl₃ + 4H₂O

Conclusion:

The HCl + Na₂S₂O₃ reaction forms the products NaCl, H₂O, SO₂, and S metal. It is a double-displacement, redox, and precipitation reaction. It shows an irreversible exothermic reaction. It cannot form a buffer solution and has a reaction enthalpy value of -338.916 kJ/mol.

Read more facts on HCl:

Dr. Shruti Ramteke

Hello everyone, I am Dr. Shruti M Ramteke, I did my Ph.D. in chemistry. I am passionate about writing and like to share my knowledge with others . Feel free to contact me on linkedin