Class 7 Science MCQ Acids, Bases and Salts

Question : Give the chemical name of Lime water __________________________.

(a) Calcium hydroxide
(b) Magnesium hydroxide
(c) Ammonium hydroxide
(d) Sodium hydroxide

Question : On adding phenolphthalein indicator to a colourless solution, no change is observed. What is the nature of this solution?

(a) Basic
(b) Either acidic or basic
(c) Either acidic or neutral
(d) Either basic or neutral

Question : Acid used in eye wash is

(a) carbonic acid
(b) acetic acid
(c) benzoic acid
(d) boric acid

Question : When CO2 gas is passed through limewater, it turns milky. Which of the following compounds is responsible for this milkiness ?

(a) Calcium oxide
(b) Calcium chloride
(c) sodium carbonate
(d) Calcium carbonate

Question : Give the chemical name of Milk of magnesia __________________________.

(a) Calcium hydroxide
(b) Magnesium hydroxide
(c) Ammonium hydroxide
(d) Sodium hydroxide

Question : Which feels soapy on touch ?

(a) Acids
(b) Bases
(c) Both (a) and (b)
(d) None of these

Question : Which of the following are special type of substances that arc used to test whether a substance is acidic or basic ?

(a) Indicators
(b) Insulators
(c) Conductors
(d) None of these

Question : The solutions which do not change the colour of either red or blue litmus are known as:

(a) acidic solution
(b) basic solution
(c) salty solution
(d) neutral solution

Question : Give the chemical name of Window cleaner __________________________.

(a) Calcium hydroxide
(b) Magnesium hydroxide
(c) Ammonium hydroxide
(d) Sodium hydroxide

Question : Litmus paper (purple colour) in distilled water when added to an acid changes to

(a) Red
(b) Blue
(c) Green
(d) Violet

Question : The solutions which do not change the colour of either red or blue litmus are known as __________________________.

(a) Acid Solutions
(b) Base Solutions
(c) Neutral Solutions
(d) indicator

Question : Find the natural indicator from the following __________________________.

(a) China Rose
(b) Vinegar
(c) Phenolphthalein
(d) Methyl Orange

Question : Phenolphthalein gives ____________colour in acid medium __________________________.

(a) Pink
(b) Colourless
(c) Green
(d) Red

Question : The sting of an ant contains ___________. __________________________.

(a) Hydrochloric acid
(b) Formic acid
(c) sulphuric acid
(d) Ethanoic acid

Question : The effect of sting of an ant can be neutralised by rubbing with __________________________.

(a) Calcium carbonate
(b) Sodium Carbonate
(c) Sodium hydrogen carbonate
(d) Calciumchloride

Question : Acids are __________________________.

(a) Sour in taste
(b) Sweet in taste
(c) salty in taste
(d) Bitter in taste

Question : Bases are __________________________.

(a) Sour in taste
(b) Sweet in taste
(c) salty in taste
(d) Bitter in taste

Question : The substances that are used to test whether a substance is acidic or basic is called __________________________.

(a) Indicator
(b) Acid
(c) Base
(d) Salt

Question : Blue litmus paper is dipped in a solution. It remains blue. What is the nature of solution ?

(a) Acid and base
(b) Base and neutral
(c) Acid apd neutral
(d) None of these

Question : Which feels soapy on touch ?

(a) Acids
(b) Bases
(c) Both (a) and (b)
(d) None of these

Question : Which of the following ion is responsible for the acidic nature of hydrochloric acid ?

(a) Hydrogen ion
(b) Hydroxide ion
(c) Chloride ion
(d) Hydrochloride ion

Question : The reaction in which an acid react with a base to form salt and water is called as

(a) Addition reaction
(b) Displacement reaction
(c) Neutralisation reaction
(d) Substitution reaction

Question : Out of these gases which one is used in fire extinguishers

(a) CO₂
(b) SO₂
(c) NO₂
(d) H₂S

Question : Litmus is extracted from

(a) curd
(b) grapes
(c) lichens
(d) cabbage

Question : Litmus is extracted from

(a) curd
(b) grapes
(c) lichens
(d) cabbage

Question : Process in which acids and bases react to form salt and water is called

(a) neutralisation
(b) hydrogenation
(c) sublimation
(d) all of these

Question : Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed.

(a) Yellow in both acid and base
(b) Yellow in acid and red in base
(c) Pink in acid and yellow in base
(d) Red in acid and blue in base

Question : Acids taste

(a) sour
(b) sweet
(c) bitter
(d) salty

Question : Neutralisation reactioñ is a

(a) physical and reversible change
(b) physical and irreversible change
(c) chemical and reversible change
(d) chemical and irreversible change

Question : How will you classify the reaction between NaOH (aq) and HCl (aq)?

(a) Conbination
(b) Displacement
(c) Dissociation
(d) Neutralisation

Question : When we suffer from acidity, we should take

(a) iron tonic
(b) vitamins
(c) antacid
(d) lactocalamine

Question : The nature of bases is

(a) acidic
(b) basic
(c) neutral
(d) all of these

Question : In neutralisation reaction:

(a) heat is absorbed
(b) heat is evolved
(c) neither heat is absorbed nor evolved
(d) none of these

Question : When phenolphthalein is added to a acidic solution, it gives

(a) pink colour
(b) red colour
(c) blue colour
(d) no colour

Question : Neutralisation is a reaction between

(a) two acids
(b) two bases
(c) one acid and one base
(d) one acid and one neutral substance

Question : Which of the following substances makes the fruits sound.

(a) Acids
(b) Salts
(c) Bases
(d) None of these

Question : The colour of litmus in distilled water is:

(a) red
(b) green
(c) blue
(d) purple

Question : Ammonia that turns red litmus blue is:

(a) acidic
(b) basic
(c) neutral
(d) none of these

Question : If the soil is too basic, it is treated with:

(a) quicklime
(b) salt
(c) organic matter
(d) water

Question : Which of the following turns colourless solution of phenol¬phthalein into pink solution ?

(a) Salt
(b) Base
(c) Acid
(d) All of these

Question : Magnesium hydroxide is found in:

(a) soap
(b) lime water
(c) milk of magnesia
(d) vegetable