In this post, you will find Class 10 NCERT Science Activity 2.6 Explanation in detail. This activity is based on chapter 2 Acids, Bases and Salts of class 10 science.
Class 10 NCERT Science Activity 2.6 Explanation
Activity- Take about 2 ml
of dilute NaOH solution in a test tube and add two drops of phenolphthalein
solution.
· What
is the colour of the solution?
· Add
dilute HCI solution to the above solution drop by drop.
· Is
there any colour change for the reaction mixture?
· Why
did the colour of phenolphthalein change after the addition of an acid?
· Now
add a few drops of NaOH to the above mixture.
· Does
the pink colour of phenolphthalein reappear?
· Why
do you think this has happened?
Observation:
When phenolphthalein is added to NaOH
solution, the solution turns pink but colour disappears on adding a few drops of
HCI to it.
NaOH+HCl → NaCl + H2O
Conclusion:
This experiment shows that the addition of HCI solution destroys the alkaline
nature of NaOH. On the other hand, the addition of NaOH solution destroys the
acidic nature of HCI, i.e., both NaOH and HCI appear to cancel the effect of
each other.
Watch the Activity 2.6 Class 10 Science Video
Answer the following questions
Q1. What is a neutralization
reaction?
Ans. -The reaction between an acid and a base to give salt and water is known as a neutralisation reaction.
Q2. Write one chemical equation for the above
reaction.
Ans. - NaOH + HCl → NaCl + H2O
3. What will happen if we add phenolphthalein in hydrochloric acid?
Ans.- When phenolphthalein
is added to hydrochloric acid, phenolphthalein remains colourless.
4. What
happens when you add phenolphthalein to sodium hydroxide?
Ans. – When phenolphthalein is added to sodium
hydroxide(a base), phenolphthalein changes to pink colour.
5. Which
reaction takes place between a base and an acid?
Ans. – Neuterlisation reaction
Related Topics -
1. Activity 2.7
2. Activity 2.5
