Correct Answer:
(A) Base
Antacids are bases. They are formed by aluminum hydroxide, magnesium hydroxide, magnesium carbonate, magnesium trisilicate, calcium carbonate etc. It is used as a medicine to reduce excessive acid formed in stomach or prevent it from forming.
Ques: 2
Goldsmiths uses aqua regia, which is prepared by mixing–
Correct Answer:
(B) Nitric acid and Hydrochloric acid
Aqua regia is an acidic, corrosive and oxidative mixture of three parts concentrated hydrochloric acid (HCl) and one part concentrated nitric acid (HNO3). It is called aqua regia because it is one of the few acid mixtures that can dissolve the 'noble' metals- Gold (Au), Platinum (Pt) and Palladium (Pd).
Ques: 3
pH value shows the Numeric value of –
Correct Answer:
(B) Analysing the acidic or basic nature of a solution
The pH scale measures the acidity or basicity of a solution. The solution with a pH less than 7 is said to be acidic while the solution with the pH greater than 7 is basic or alkaline. The pure water has a pH value 7. The logarithm of the reciprocal of hydrogen ion concentration in moles per litre is measured by pH scale from 0 to 14.
Ques: 4
The pH of a solution changes from 3 to 6. The H+ ion concentration will :
Correct Answer:
(D)
decrease 1000 times
pH is a logarithmic scale used to specify the acidity or basicity (alkalinity) of an aqueous solution. It inversely indicates the concentration of hydrogen ions (H+) in the solution as it approximates the negative of the base 10 logarithm of the molar concentration of hydrogen ions (H+) in a solution. Each number represents a 10-fold change in the acidity/basicity of the solution. If the pH number is increased by 1, it means H+ ion concentration is decreased by 10 times. Hence, if the pH of a solution changes from 3 to 6, the H+ ion concentration will decrease 1000 times, and it will become less acidic.
Ques: 5
Which of the following has pH value 7?
Correct Answer:
(D)
None of the above/More than one of the above
The pH value of pure water and neutral solution is 7. In general, water with pH lower than 7 is considered acidic and greater than 7 is considered basic. Pure water is considered neutral.
Ques: 6
A solution turns red litmus blue. The pH of solution is :
Correct Answer:
(D)
more than 7
When a red litmus paper is immersed in a base or alkaline, the red litmus paper turns blue indicating the given solution as alkaline/base. When a blue litmus paper is immersed in an acid, the litmus paper turns red from blue indicating acid. The solution having pH value less than 7 is acidic and the solution having pH value more than 7 would be basic. According to the question, the red litmus paper turns blue which shows alkaline/basic nature of the solution. Thus, it has the pH value more than 7.
Ques: 7
Which of the following may be a possible pH value of an acidic solution?
Correct Answer:
(A) 6
If the pH of a solution is less than 7, the solution is called acidic, if the pH is about 7 the solution is neutral and if the pH is greater than 7, the solution is called basic. In an acidic solution, the concentration of hydrogen ions (H+) is greater than the concentration of hydroxide ions (OH–).
Ques: 8
Which acid is considered as a basic chemical in Industry?
Correct Answer:
(C) H2SO4
In the chemical industry, the sulphuric acid (H2 SO4) is considered as basic chemical. Sulphuric acid is mainly used in petrochemical industries. It is used to refi ne metals, reduce corrosion of steel, refi ne oil and manufacture fertilizers. It is also used for cleaning purposes in the laboratory.
Ques: 9
Which of the following is present in maximum amount in acid rain?
Correct Answer:
(C) H2SO4
The sulphur dioxide and nitrous oxide emitted from atmospheric pollution, industrial effusions and other activities occurring in the nature reach the atmosphere and react with oxygen and cloud water and fall on earth as sulphuric acid (H2SO4) and nitric acid (HNO3) respectively. This is called Acid rain. The amount of sulphuric Acid (H2SO4) in the acid rain is about 70-75% and it is the primary acid rain component.
Ques: 10
An aqueous solution of copper sulphate is acidic in nature because the salt undergoes –
Correct Answer:
(C) Hydrolysis
Copper sulphate reacts with water which produces strong acid H2SO4 and weak base Cu(OH)2 as there is a process of hydrolysis. So, it is acidic in nature.
CuSO4 + 2H2O → H2SO4 + Cu(OH)2
Ques: 11
Which is NOT a Lewis acid?
Correct Answer:
(C) NH3
The Lewis acids are lone pair acceptors. The Lewis bases are lone pair donors. Nitrogen in NH3 has 5 electrons in which 3 of them are involved in bonding. That leaves one lone pair. This lone pair is available for bonding. Therefore, NH3 is a Lewis base. AlCl3, BF3 and FeCl3 are Lewis acids.
Ques: 12
Consider the following statements:
Assertion (A) : To dilute sulphuric acid, acid is added to water and not water to acid.
Reason (R) : Specific heat of water is very high.
(A) and (R) are true, and (R) is the correct explanation of
(A).
Correct Answer:
(A) and (R) are true, but (R) is not a correct explanation of
Ques: 13
Limewater is turned milky by:
Correct Answer:
(B) CO2
Carbon dioxide (CO2) reacts with calcium hydroxide to produce a white precipitate of calcium carbonate. Limewater is a solution of calcium hydroxide. So, if carbon dioxide is passed through limewater, the limewater will turn milky or cloudy white.
Ca(OH)2 + CO2 → CaCO3 + H2O
Ques: 14
Soda water obtained by passing carbon dioxide in water is :
Correct Answer:
(C) Acidic in nature
The carbon dioxide (CO2) gas dissolved in water can cause water to become acidic. The acidity of water from dissolved CO2 can be reduced by a base such as baking soda (Sodium bicarbonate). When carbon dioxide is dissolved in the water, it forms carbonic acid (H2CO3) by reacting with water (H2O) and remains in dissolved state at high pressure. So, the soda- water becomes acidic in nature.
Ques: 15
Which of the following acid do not contain oxygen –
Correct Answer:
(C) Hydrochloric Acid
Hydrochloric Acid (HCl) does not contain oxygen, as it is a compound of hydrogen and chlorine.
Ques: 16
An unknown gas quickly dissolves in water. This gaseous aqueous solution turns red litmus into the blue. This gas produces white flame with hydrogen chloride.
This unknown gas is –
Correct Answer:
(C) Ammonia
The aqueous solution of ammonia is basic due to forming of ammonium hydroxide which changes the colour of red litmus into blue. Ammonia produces a white flame when it reacts with hydrochloric acid.
Ques: 17
Match List-I with List-II and select the correct answer from the code given below the lists.
List-I List-II
Bleaching powder 1. Sodium bicarbonate
Baking soda 2. Sodium carbonate
Washing powder 3. Calcium oxychloride
Plaster of Paris 4. Calcium sulphate hemihydrate
Code :
A B C D
Correct Answer:
(C) 3 1 2 4
The correctly matched lists are as follows :
List-I List-II
Bleaching powder - Calcium oxychloride (CaOCl2 )
Baking soda - Sodium bicarbonate (NaHCO3 )
Washing powder - Sodium carbonate (Na2CO3 )
Plaster of Paris - Calcium sulphate hemihydrate (CaSO4 .½H2O)
Ques: 18
What is Neela thotha?
Correct Answer:
(A) Copper Sulphate
Neela thotha (blue vitriol) is a compound of copper and sulphate. Its chemical formula is CuSO4.5H2O.
Ques: 19
The chemical used for destroying fungi in water tank is :
Correct Answer:
(D)
Copper Sulphate
Copper sulphate (blue vitriol or neela thotha) is used for destroying fungi in water tank. It is also used as a fungicide to protect field crops.
Ques: 20
Match the following lists by using codes given below. Select the correct answer?