NCTB Class 9-10 Science Chapter 7 “Use of Acid, Base and Salt” Solution
Bangladesh Board Class 9-10 Science Solution Chapter 7 Use of Acid, Base and Salt Solution Exercises Question and Answer by Experienced Teacher.
NCTB Solution Class 9-10 Chapter 7 “Use of Acid, Base and Salt”:
|NCTB Bangladesh Board|
9 – 10 (Nine – Ten Classes)
Use of Acid, Base and Salt
Multiple choice questions
1) Which is weak acid ?
a) Hclb) HNo3
c) H2Co3 d) H2so4
Answer:- c) H2Co3
2) Upon the addition of sodium hydroxide to a colourless solution , it turns into violet. Which chemical is present in the solution ?
a) Methyl red b) methyl orange
b) Phenolphthalein d) Litmus solution
Answer:- b) phenolphthalein
Read the following paragraph and answer questions 3 and 4.
Raji suffered from pain and swelling severely as ants bite on her foot. Her mother gave her a caramine lotion to apply on the wounded part. As a result she got relief from pain.
3) What is the cause of swelling on rayi’s foot ?
a) Formic acid b) oxalic acid
b) acetic acid d) citric acid
Answer:- formic acid
4) Lotion used on foot –
I. Neutralizes acid
II. Is ZnCo3 salt
III. Acid named melittin and Apamin
Which of the following is correct?
a) I and ii b) I and iii
c ) ii and iii d) I, ii, and iii
Answer:- d) I, ii, and iii
Que.1] Ontu prefers meat, oily food and chocolate . One day he had been suffering from indigestion after eating Biryani. His mather gave him a soft beverage to drink and he came round gradually. On the other hand, his sister sholini, likes soya milk, soya butter, and fruits very much.
A) Which acid is used for the preservation of pickles ?
Answer:- Acetic acid which is also known as Vinegar is used to preserve pickles.
B) What is meant by the term ‘weak acid’ ?
Answer:- Acids produces H+ ion in water . There are some acids particularly organic acids, which do not dissociate completely in water. i.e they dissociate partially which means all the acid molecule present do not produce H+ ion . These are called weak acids. E.g – citric acid, oxalic acid, acetic acid.
C) How did ontu come around?
Answer:-ontu prefers meat, oily food, chocolate and Biryani. Due to these excessive intake of foodontu got an indigestion i.e Acidity. For the digestion of food hydrochloric acid is required in the stomach in a particular amount. If the amount of the acid is increases in the stomach that condition is termed as acidity in stomach.
D) If you compare between the food choice of ontu and sholini, whose food is responsible for acidity? Explain.
Answer:- in comparison of food Of ontu and sholini, ontu’s choice of food is responsible for acidity.
Excessive intake of food of ontu’s choise increase the level of hcl in stomach thus cause the acidity.
Que.2] Mr. Tuhin often suffers from stomach upset. He went to a doctor who advice to check pH of stomach and arterial blood. Diagnosis report showed that the phlevelin stomach and blood was 1.5 and 7.5 respectively. When he was returning home with the report, he went to buy a lotion of ph5.5 for her daughter who is two months old. But the shopkeeper suggested him to buy another lotion.
A) Write down the chemical formula of ammonium sulphate.
Answer:- the chemical formula of ammonium sulphate is [(NH4)2So4].
B) Why is vinegar called a weak acid?
Answer:- Acid produces hydrogen ion (H+) in water . There are some acids, particularly organic acids, which do not dissociate completely in water. i.e they dissociate partially which means all the acids molecules present do not produce H+ ion. These acids are called weak acid. Thus acetic acid or vinegar is weak acid.
C) Why did the shopkeeper prohibited mr. Tuhin to buy the lotion of pH 5.5? Explain.
Answer:-the pH of matured human skin is acidic and it ranges from 4.0 – 6.0 however the pH of newbornbabies skin is close to 7. Therefore most of the cosmetic used for the adult should not use be used by kids. It may cause severe damaged to skin. Thus the shopkeeper prohibited mr. Tuhin to buy ph 5.5 lotion.
D) Is the level of pH in mr. Tuhin’sblood appropriate ? Give your opinion.
Answer:- the pH in mr. Tuhin’s blood is quite appropriate. pH of human blood (arterial) is 7.4 i.eit is slightly alkaline . Mr. Tuhin has the blood pH 7.5 is quite appropriate. The alternation of +0.4 or -0.4 in pH of blood may cause serious health issues.