# Ncert Science Class 10 Solutions Chapter 2

## Ncert Science Class 10 Solutions Chapter 2 Acid Bases and Salts

Welcome to NCTB Solutions. Here with this post we are going to help 10th class students for the Solutions of NCERT Class 10 Science Book Chapter 2, Acids Bases and Salts. Here students can easily find step by step solutions of all the questions in Acids Bases and Salts. Also our Expert Science Teacher’s solved all the problems with easily understandable language with proper guidance so that all the students can understand easily. Here in this post students will get chapter 2 solutions. Here all Question Answer are based on NCERT latest syllabus.

Acids Bases and Salts Exercise question Solutions :

(1) A solution turns red litmus blue, its pH is likely to be

Answer :

The correct option is – (d)

Its pH is likely to be 10.

Because Base has Ph from 7 – 14 which turns red litmus blue.

(2) A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains

Answer :

The correct option is – (b) HCl (hydrochloric acid)

Because egg shell is made up of calcium carbonate.

2HCl + CaCO3→ CaCl2 + H2O + CO2

Hydrochloric acid Calcium Carbonate Calcium chloride water carbon dioxide.

(3) 10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. If we take 20 mL of the same solution of NaOH, the amount HCl solution

Answer :

The amount HCl solution (the same solution as before) required to neutralise it will be,

For 10 mL NaoH = 8 mL HCl

For 20(10*2) mL NaOH = 16(8*2) mL HCl

(4) Which one of the following types of medicines is used for treating indigestion?

Answer :

The correct option is – (c)

Antacid is used for treating indigestion

Our body create HCl for digestion of food. More than needed acid create pain. To nullify acid we take alkalis ,that is called antacid.

(5) Write word equations and then balanced equations for the reaction taking place when

Answer :

(a) dilute sulfuric acid reacts with zinc granules.

= Sulfuric acid Zink Zink Sulphate Hydrogen

= H2SO4 + Zn → ZnSO4+ H2

(b) dilute hydrochloric acid reacts with magnesium ribbon.

= Hydrochloric acid magnesium magnesium chloride Hydrogen

= 2HCl + Mg → MgCl2 + H2

(c) dilute sulfuric acid reacts with aluminum powder.

= Sulfuric acid aluminum aluminum sulphate hydrogen

= 3H2SO4 + 2Al → Al(SO4)3 + 3H2

(d) dilute hydrochloric acid reacts with iron filings.

= Hydrochloric acid Ferrous Ferrous chloride hydrogen

= HCl + Fe → FeCl + H2

(6) Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it.

Answer :

• Take solution of glucose and alcohol.
• Fix two nails on a cork and place the cork in a 100 mL beaker.
• Connect the nails to the two terminal of battery through a bulb and switch as shown.
• Now pour some glucose solution in beaker and switch on the current.
• Observe current is not passing through glucose solution because bulb is not glowing.
• Repeat activity no 4 for alchohol solution.

Bulb will not glow in this case also, by this we can prove by thatglucose and alchohol is not acid.

(7) Why does distilled water not conduct electricity, whereas rain water does?

Answer :

To conduct electricity water should have ionic compound in it. Ionic compounds have cation to (negative ion) and ionoin (positive ion) to conduct electricity. They are pressure in rain water because of acid and salts are pressure in water.

Example :  Acidic rain, Salty water due to impurities from soil. Distilled water is pure form all of these. So, it doesn’t conduct electricity.

(8) Why do acids not show acidic behaviour in the absence of water?

Answer :

To show acid, acidic behavior the separation of H+ ions from acid compound is necessary.

Hydrogen ion can not exist alone, but they exist after combining with water molecules, thus acid do not show acidic behavior in absence of water.

(9) Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is

Answer :

The given solutions as following A B C D E

Now, the solution D having ph 7 is neutral

The solution B having ph 1 is strongly acidic

The solution C having Ph 11 is strongly alkaline

The solution E having ph 9 is weakly alkaline

The solution A having ph 4 is weakly acid.

(10) Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. Amount and concentration taken for both the acids are same. In which test tube will the fizzing occur more vigorously and why?

Answer :

Fizzing means making a bubbling sound. By realizing hydrogen from acid. Mg ribbon is equal. And acid also, but the HCl is more strong acid than acetic acid. So the reaction of acid is more in test tube A and fizzing occur more vigorously in test tube A.

(11) Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.

Answer :

Curd is sour, Acid shows sour test. Fresh milk has 6 Ph which is weakly acidic in nature. After milk turn in curd the Ph will drop down.

(12) A milkman adds a very small amount of baking soda to fresh milk.

Answer :

(a) Why does he shift the pH of the fresh milk from 6 to slightly alkaline?

= Fresh milk have acidic Ph of 6. By adding Baking soda Alkaline, Milkman slower down the process of setting the curd.

(b) Why does this milk take a long time to set as curd?

= Fresh milk has 6 Ph After adding soda milk becomes slightly alkaline, to set curd it first becomes Neutral at 7 than comes to weakly acidic 6. And the starts to set curd . this Process take time.

(13) Plaster of Paris should be stored in a moisture-proof container. Explain why?

Answer :

POP is made of Gypson. The use of POP is to make any hard shape by adding water and letting it dry.

But when the moisture container is not used for storing the powder of POP then the moisture hardens the POP.

(14) What is a neutralization reaction? Give two examples.

Answer :

The reaction between acid and base to give salt and water is known as neutralization reaction.

NaOH + HCl → NaCl + H2O
Sodium hydroxide hydrochloric acid sodium chloride water

3NaHCO3 + C6H8O7 → C6H5Na3O7 +3H2O + 3CO2

Baking soda citric acid salt water carbon dioxide.

(15) Give two important uses of washing soda and baking soda.

Answer :

Examples of washing soda :

• To clean cloths and kitchen utensils.
• As catalyst in glass making in silica.

Example of baking soda :

• As antacid for digestion.
• In baking for bread.
• For maintaining Ph in milk for long shelf life.

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Updated: June 30, 2023 — 7:20 am