Here are some important questions of Class 10 Chemistry Acid Base and Salt chapter MCQs
Q-1: If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
(a) Wash the hand with saline solution
(b) Wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonate
(c) After washing with plenty of water apply solution of sodium hydroxide on the hand
(d) Neutralise the acid with a strong alkali
Q-2:Which of the following phenomena occur, when a small amount of acid is added to water?
(i) Ionisation (ii) Neutralisation (iii) Dilution (iv) Salt formation
Q-3:A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains
(a) NaCl (b) HCl (c) LiCl (d) KCl
Q-4:When NaOH and HCl are mixed in equal molar quantities, the result is
(a) the formation of salt + H2O (b) the formation of salt + H2(g)
(c) the formation of salt + O2(g) (d) All above are correct
Q-5:Ans : (a) the formation of salt + H2O
When NaOH and HCl are mixed in equal molar quantities, acid-base reaction takes place and we get salt (NaCl) and water.
NaOH +HCl ———-à NaCl +H2O
Aqueous solution of copper sulphate reacts with aqueous ammonium hydroxide solution to give.
Q-6:(a) brown precipitate (b) pale blue precipitate (c) white precipitate (d) green precipitate
Ans : (b) pale blue precipitate
Q-7:CuSO4(aq) + 2NH4OH (aq) ———à Cu (OH)2(s) + (NH4)2SO4(s) When aqueous solution of copper sulphate react with aqueous ammonium hydroxide solution, then pale blue precipitate of Cu (OH)2 are formed.
Which of the following is acidic in nature-
(a) apple juice (b) soap solution
(c) slaked lime (d) lime
Ans : (a) apple juice
You are having five solutions A, B, C D and E with pH values as follows:
A=18, B=7, C =8.5, D = 8 and E = 5
Q-8:Which solution would be most likely to liberate hydrogen with magnesium powder?
(a) Solution A and B (b) Solution A
(c) Solution C (d) All of the above
(b) Solution A
Solution A would liberate hydrogen with magnesium because pH value is least for A solution i.e. 1.8. Hence, it is the most acidic among all the solutions.
Q-9:The correct statement regarding universal indicator is
(a) it is an indicator having pH = 7
(b) it gives blue colour at pH = 3
(c) it becomes colourless at pH = 7
(d) it gives orange colour at pH = 3
(d) it gives orange colour at pH = 3
Universal indicator is mixture of many indicators. Its colour is orange at pH = 3.
Q-10:The pH of a solution is 4.0 ,What should be the change in the hydrogen ion concentration of the solution, if its pH is to increased to 5.0.
(a) decreases to 1/10 of its original concentration
(b) halved
(c) doubled
(d) increases by 10 times
Q-11: Bottle A contains acetic acid and bottle B contains sodium carbonate solution. When pH paper is dipped in each of the solution, the colour seen in A and B respectively will be:
(a) blue, orange (b) orange, green (c) orange, blue (d) green, blue
Ans: (c) orange, blue
(a) decreases to 1/10 of its original concentration
The pH of a solution is 4.0. When pH of a solution increases, the hydrogen ion concentration decreases to 1/10 of its original concentration.
PH = – log [H+]
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Class 10 Chemistry Acid Base and Salt chapter MCQs: Assertion and Reason type Question
For Assertion& Reason question follow the following directions.
DIRECTION: Each of these questions contains an Assertion followed by Reason. Read them carefully and answer the question on the basis of following options. You have to select the one that best describes the two statements.
(a) If both Assertion and Reason are correct and Reason is the correct explanation of Assertion.
(b) If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion.
(c) If Assertion is correct but Reason is incorrect.
(d) If Assertion is incorrect but Reason is correct.
Assertion: Sodium hydroxide reacts with zinc to produce hydrogen gas.
Reason: Acids reacts with active metals to produce hydrogen gas.
Ans: (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Sodium hydroxide being a strong base reacts with active metal (zinc) to product H2 gas. The reaction is given as follows:
Zn (s) + 2NaOH (aq) ————–à Na2ZnO2(aq) +H2(g)
Assertion: Salts are the products of an acid-base reaction.
Reason : Salt may be acidic or basic.
Ans : (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A)
Assertion: H2CO3 is a strong acid.
Reason: A strong acid dissociates completely or almost completely in water.
Ans : (d) Assertion (A) is false but reason (R) is true. H2CO3 carbonic acid is a weak acid.
Assertion: Weak acids have low electrical conductivity.
Reason: Strong acids and weak acids have equal concentration of hydrogen ions in their solutions.
Ans : (c) Assertion (A) is true but reason (R) is false.
Assertion : Pure water is neither acidic not basic.
Reason: The pH of a solution is inversely proportional to the concentration of hydrogen ions in it.
Ans : (b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
Assertion : pH = 7 signifies pure water.
Reason : At this pH, [H+] = [OH ] = 107
Ans : (d) Assertion (A) is false but reason (R) is true.
pH = 7,signifies neutral solution.
Assertion: The strength of acids and bases depends on the number of ions and ions produced respectively, when dissolved in water.
Reason: Acids like HClO4 which dissociate almost completely in water are called acids.
Ans-(a)
Explanation: Mixing of acid and water during dilution is an exothermic reaction. So if water is added to acid, lots of heat energy is released which may cause accidents
(b) Sulphuric acid dissociates into ions in the solution but alcohol does not
(c) Solution of ammonia in water produces OH- ions which makes the solution basic and turns red litmus blue
Assertion: Weak acids have low electrical conductivity.
Reason: Strong acids and weak acids have equal concentration of hydrogen ions in their solutions.
Ans: (a) , Explanation: Take aqueous solutions of glucose ( C6H12O6) and ethyl alcohol (C2H5OH) and test for electrical conductivity. Both the solutions do not conduct electricity. Test with blue litmus paper both of them will not turn blue litmus red.
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