15 Facts on H2SO4+ NACLO2: What, How To Balance & FAQs

Sulphuric acid reacts with chlorous acid, sodium salt forms four different compounds. Let us study the reaction of H₂SO₄ + NaClO₂ in detail.

Sulfuric acid is a viscous, colorless, and miscible in water, odorless liquid. It is an important commodity and industrial compound, produced from various different methods. Sodium chlorite is usually found in industrial setting as a detergent and as bleach. It is produced from two ways reduction and electrolysis.

The following article studies the various fact of H₂SO₄ + NaClO₂  reactions like the reaction type, product, conjugate pairs, enthalpy of reaction, ionic equation etc.

What is the product of H₂SO₄ and NaClO₂?

Sulfuric acid (H₂SO₄) reacts with sodium chlorite (NaClO₂) to form chlorine dioxide (ClO₂), sodium sulfate (Na₂SO₄), water (H₂O) and sodium chloride (NaCl). Any one of the following reaction may occur,

NaClO₂ + H₂SO₄ → ClO₂ + Na₂SO₄ + H₂O + NaCl  

OR,

2NaClO₂ + H₂SO₄ → Na₂SO₄ + 2HClO₂

What type of reaction is H₂SO₄ + NaClO₂?

H₂SO₄ + NaClO₂ is a gas evolution reaction, redox reaction and precipitate reaction.

How to balance H₂SO₄ + NaClO₂?

To balance the given chemical reaction following steps are followed:

• The unbalanced chemical reaction is written as:
• H₂SO_{4 +} NaClO₂ → ClO₂ + Na₂SO₄ + H₂O + NaCl                
• The respective number of moles of each element are tabulated as shown below :

Elements	Reactant Side	Product Side
Na	1	3
Cl	1	2
S	1	1
O	6	7
H	2	2

• The given reaction is balanced when number of moles of Na, Cl, S, O and H are balanced on either side of the reaction.
• Here moles of each elements are unbalanced on either side.
• To balance the reaction, following multiplication is carried out:
  1. Multiply 2 with H₂SO₄ , reactant side
  2. Multiply 5 with NaClO₂, reactant side
  3. Multiply 4 with ClO₂, reactant side
  4. Multiply 2 each with Na₂SO₄ and  H₂O on product side

• The Balanced chemical reaction is
• 2H₂SO₄ +5NaClO₂ → 4ClO₂ + 2Na₂SO₄ + 2H₂O + NaCl

H₂SO₄ + NaClO₂ titration

H₂SO_{4 +} NaClO₂ titration is not possible since the reaction leads to the formation of gas, ClO₂ .

H₂SO₄ + NaClO₂ net ionic equation

The net ionic equation is – 5ClO₂^–(aq) + 4H⁺(aq) = 4ClO₂(g) + 2H₂O(l) + Cl^–(aq)

• First, the phase or state of each compound is determined as shown below:
• 5NaClO₂(aq) + 2H₂SO₄(aq) = 4ClO₂(g) + 2Na₂SO₄(aq) + 2H₂O(l) + NaCl(aq)
• Second, complete ionic equation is written by separating the ionic compounds into their respective ions,
• 5Na⁺(aq) + 5ClO₂^–(aq) + 4H⁺(aq) + 2SO₄^2-(aq) = 4ClO₂(g) + 4Na⁺(aq) + 2SO₄^2-(aq) + 2H₂O(l) + Na⁺(aq) + Cl^–(aq)
• The common ions present in the both reactant and product sides are removed.
• 5Na⁺(aq) + 5ClO₂^–(aq) + 4H⁺(aq) + 2SO₄^2-(aq) = 4ClO₂(g) + 4Na⁺(aq) + 2SO₄^2-(aq) + 2H₂O(l) + Na⁺(aq) + Cl^–(aq)
• The net ionic equation involves compounds which are taking place in the reaction.
• The net ionic equation is –
• 5ClO₂^–(aq) + 4H⁺(aq) = 4ClO₂(g) + 2H₂O(l) + Cl^–(aq)

H₂SO₄ + NaClO₂ conjugate pairs

The conjugate acid-base pairs for H₂SO₄ + NaClO₂ are,

• Conjugate acid of H₂SO₄ =  H₃O⁺
• Conjugate base of H₂SO₄  = HSO₄^– 
• Conjugate acid of NaClO₂  = HClO⁺
• Conjugate base of NaClO₂  = ClO₂^– 

H₂SO₄ + NaClO₂ intermolecular forces

The intermolecular forces on H₂SO₄ and NaClO₂ are-

• Van der Waals dispersion forces, Dipole-dipole interaction, and  Hydrogen bond acts on H₂SO₄.
• Ion- dipole forces act on NaClO₂

H₂SO₄ + NaClO₂ reaction enthalpy

H₂SO₄ + NaClO₂ change in reaction enthalpy is, -1141.16 kJ/mol.

• The reaction enthalpy of formation of each compound on the either side of the reaction is tabulated down as:

Compounds	Enthalpy (kJ/mol)
H2SO4	-909.27
NaClO2	-307
Na2SO4	-1387.1
ClO2	102.5
NaCl	-787
H2O	-285.83

• Change in reaction enthalpy = Sum of enthalpies in product side – sum of enthalpies in reactant side.
• Change in Enthalpy  =  (-1387.1+102.5-787-285.83) – (-909.27-307) = -1141.16 kJ/mol

Is H₂SO₄ + NaClO₂a buffer solution?

H₂SO₄ + NaClO₂ is not a buffer solution due to the presence of strong H₂SO₄  acid in the reaction.

Is H₂SO₄ + NaClO₂ a complete reaction?

H₂SO₄ + NaClO₂ is defined as a complete reaction since moles of reactant are completely consumed to yield products at equilibrium.

Is H₂SO₄ + NaClO₂ an exothermic or endothermic reaction?

H₂SO₄ + NaClO₂ is an exothermic reaction because the change in enthalpy is -1141.16 kJ/mol, which is negative thereby increasing the temperature.

Is H₂SO₄ + NaClO₂ a redox reaction?

H₂SO₄ + NaClO₂ is a redox reaction.

• Reduction, Cl^III + 4e^– → Cl^-I
• Oxidation, 4Cl^III – 4e^– → 4Cl^IV

Is H₂SO₄ + NaClO₂ a precipitation reaction?

H₂SO₄ + NaClO₂ is a precipitation reaction, due to the formation of salt NaCl during the reaction.

Is H₂SO₄ + NaClO₂ reversible or irreversible reaction?

H₂SO₄ + NaClO₂ is not a reversible reaction, unless and until there is drastic change in experiment pressure or temperature.

Is H₂SO₄ + NaClO₂ displacement reaction?

H₂SO₄ + NaClO₂ reaction is a double displacement (metathesis) reaction, as Na is displaced twice to form the product.

Conclusion

Reaction of sulfuric acid with sodium chlorite involves formation of gas (ClO₂) and formation of salt (NaCl). Sodium sulfate is mainly used as filler in production of detergents, in Kraft process of paper pulping. Sodium chloride is used as feedstocks for different chemical synthesis and is an important industrial chemical.