NCERT Solutions for Class 7 Science Chapter 5
Important NCERT Questions
7th Chapter 5 Acids, Bases and Salts
NCERT Books for Session 2022-2023
CBSE Board and State Board
Questions No: 5
Describe the process of neutralisation with the help of an example.
Share
When an acid solution and a base solution are mixed in suitable amounts, both the acidic nature of the acid and the basic nature of the base are destroyed. The resulting solution is neither acidic nor basic, it become neutral. This process is known as neutralisation reaction.
Fill one fourth of a test tube with dilute hydrochloric acid and add few drop of litmus solution. Now the colour of the solutions become red. Now add to this acidic solution drops of sodium hydroxide solution gradually one by one with a dropper. Stir the tube gently. Continue adding the sodium hydroxide solution drop by drop while stirring till the colour just become green. Now the effect of hydrochloric acid is neutralized by the base sodium hydroxide.
https://www.tiwariacademy.com/ncert-solutions/class-7/science/chapter-5/
Neutralization is a chemical reaction occurring between an acid and a base, culminating in the formation of salt and water. Here’s an illustrative example demonstrating neutralization:
Example – Neutralization of Hydrochloric Acid (HCl) with Sodium Hydroxide (NaOH):
1. Reactants:
– Hydrochloric Acid (HCl): An acid rich in hydrogen ions (H⁺).
– Sodium Hydroxide (NaOH): A base releasing hydroxide ions (OH⁻).
2. Chemical Equation: The neutralization reaction is symbolized by the equation:
HCl + NaOH → NaCl + H₂O
– Hydrochloric acid reacts with sodium hydroxide, yielding sodium chloride (salt) and water.
3. Reaction Process:
– HCl disintegrates in water, yielding hydrogen ions (H⁺) and chloride ions (Cl⁻).
– NaOH breaks down in water, producing sodium ions (Na⁺) and hydroxide ions (OH⁻).
– Hydrogen ions (H⁺) from the acid combine with hydroxide ions (OH⁻) from the base, generating water (H₂O).
– The remaining ions amalgamate, creating the salt sodium chloride (NaCl).
4. Result: The reaction yields sodium chloride (NaCl), a neutral salt, and water (H₂O). Consequently, the resultant solution is neutral, approximating a pH of 7.
5. Observation: The reaction may emit heat due to its exothermic nature. In addition, water vapor might form if the reaction occurs in an unsealed container.
This instance exemplifies how the combination of an acid and a base results in neutralization, forming a salt and water, effectively nullifying the acidic and basic properties of the initial substances.