39 questions · timed · auto-graded
Explanation:
Indigestion is caused by the formation of excess acid in the stomach. An antacid is a medicine that is generally a base or a basic salt that neutralises acidity in the stomach.
Explanation:
KCl is formed from a strong acid, hydrochloric acid (HCl), and a strong base, potassium hydroxide (KOH). Thus, KCl, on hydrolysis, forms equal amounts of H+ and OH- ions. This is why an aqueous solution of KCl shows a pH of almost 7.
Explanation:
Bleaching powder (CaOCl2) is formed by passing chlorine gas over slaked lime [Ca(OH)2].
Explanation:
When a wasp stings a person, it inserts an alkaline solution into the person's skin. This causes high irritation and pain. Applying a weak acid, such as vinegar, to the wound neutralises the alkaline solution and soothes the pain.
Explanation:
A wasp sting injects an alkaline solution into the skin, which causes high irritation and pain.
Explanation:
Ammonium sulphate [(NH4)2SO4] is formed from a weak base, ammonium hydroxide (NH4OH), and a strong acid, sulphuric acid (H2SO4). On dissolving in water, (NH4)2SO4 hydrolyses to form more H+ ions than OH- ions. As the aqueous solution of the salt (NH4)2SO4 is acidic, it turns blue litmus red.
Explanation:
Potassium sulphate (K2SO4) is formed from a strong acid, sulphuric acid (H2SO4), and a strong base, potassium hydroxide (KOH). On dissolving in water, K2SO4 hydrolyses to form equal amounts of H+ and OH- ions. As the salt solution of K2SO4is neutral, it has no effect on red or blue litmus paper.
Explanation:
KCl is formed from a strong acid, hydrochloric acid (HCl), and a strong base, potassium hydroxide (KOH). On dissolving in water, KCl hydrolyses to form equal amounts of H+ and OH- ions. This is why an aqueous solution of KCl is neutral with a pH of almost 7.
Explanation:
NH4Cl is formed with a weak base, ammonium hydroxide (NH4OH), and a strong acid, hydrochloric acid (HCl). On dissolving in water, NH4Cl hydrolyses to form more H+ ions than OH- ions. Thus, it is acidic with a pH less than 7.
Explanation:
Acids have a sour taste, they turn blue litmus paper red and their pH is less than seven. But they do not feel soapy.
Explanation:
Vinegar and curds are acidic. They both have a sour taste.
Explanation:
The process of electrolysis of sodium chloride solution is called the chlor-alkali process because of the products formed, i.e., H2, Cl2 and NaOH. 'Chlor' stands for chlorine and 'alkali' for sodium hydroxide (NaOH).
Explanation:
The chemical formula of washing soda is Na2CO3.10H2O. The water molecules that form part of the structure of a salt are called its water of crystallisation. Hence, the number of molecules of water of crystallisation present in washing soda crystals is 10.
Explanation:
Phenolphthalein produces a pink colour in an alkali solution.
Explanation:
Litmus and methyl orange turn red in an acid solution.
Explanation:
The chemical name of baking soda is sodium hydrogen carbonate, and its chemical formula is NaHCO3.
Explanation:
Baking soda, being a base, neutralises the excess acid formed in the stomach and cures the discomfort caused by indigestion.
Explanation:
If the pH of the soil is 4.5, then it is highly acidic. Thus, soil should be treated with a base, such as quick lime (calcium oxide) or slaked lime (calcium hydroxide). These bases react with the excess acid present in the soil and neutralises it. Thus, the pH of the soil is increased, making it suitable for growing daffodils.
Explanation:
Basic or alkaline solutions turn a methyl orange indicator yellow. Thus, the pH of the solution is likely to be more than 7.
Explanation:
Potassium carbonate (K2CO3) is formed from a weak acid, carbonic acid (H2CO3), and a strong base, potassium hydroxide (KOH). On hydrolysis, K2CO3 forms more OH- ions than H+ ions. Thus, it is basic and therefore turns red litmus blue.
Explanation:
K2CO3 is formed from a weak acid, carbonic acid (H2CO3), and a strong base, potassium hydroxide (KOH). On hydrolysis, K2CO3 forms more OH- ions than H+ ions, and thus, it is basic. As the aqueous solution of the salt is basic, it turns a phenolphthalein indicator pink.
Explanation:
Our stomach produces dilute hydrochloric acid naturally. The acid that is produced, which has a pH of around 1.4, does not damage our stomach. Rather, it helps in the digestion of food.
Explanation:
When CaSO4.2H2O (gypsum) is heated to a temperature of 100⁰C (373K), it loses three-fourths of its water of crystallisation and forms plaster of Paris (CaSO4.1/2H2O).
Explanation:
Na2CO3 is formed from a weak acid, carbonic acid (H2CO3), and a strong base, sodium hydroxide (NaOH). On dissolving in water, Na2CO3 hydrolyses to form more OH- ions than H+ ions. Therefore, its solution in water is basic, or alkaline, with a pH more than 7.
Explanation:
Carbonic acid H2CO3 is formed when CO2 is dissolved in water. Hence, carbonic acid is an inorganic or mineral acid. Ethanoic acid, formic acid and citric acid are found naturally.
Explanation:
Magnesium hydroxide, which is a base, acts as an antacid. It neutralises excess acid present in the stomach and cures indigestion. Hence, it is used as a medicine.
Explanation:
A honey bee, ant and a nettle leaf hair inject methanoic acid into the skin through their stings. But a wasp injects an alkaline solution into the skin through its sting.
Explanation:
When a wasp stings a person, it injects an alkaline solution into the person's skin. This causes high irritation and pain. Applying a weak acid, such as vinegar, to the wound neutralises the alkaline solution and soothes the pain.
Explanation:
When fresh milk changes into curd, its acidity increases and it turns sour Therefore, the pH of fresh milk becomes less than 6 when milk changes into curd.
Explanation:
When a bee stings a person, it injects an acidic solution into the person’s skin, which causes severe pain and an itching sensation. Applying a baking soda solution (sodium hydrogen carbonate solution, which is a base) soothes the pain by neutralising the acid.
Explanation:
A bee sting contains an acidic solution. The name of the acid is methanoic acid.
Explanation:
A basic solution turns red litmus blue. On the pH scale, bases have values greater than 7, whereas acids have values less than 7. Therefore, the pH of the given solution is likely to be 10.
Explanation:
Every substance with a pH greater than 7 is considered basic or alkaline. Basic or alkaline solutions turn phenolphthalein indicator pink. Thus, the pH of the solution is most likely 9.
Explanation:
An acidic solution turns blue litmus red. On the pH scale, acids have values less than 7, whereas bases have values greater than 7. Solutions with pH equal to 7 are neutral in nature. Therefore, the pH of the given solution is likely to be 5.
Explanation:
Zinc granules react with HCl to give hydrogen gas, which burns with a ‘pop’ sound.
Explanation:
Marble chips contain calcium carbonate (CaCO3), which reacts with sulphuric acid (H2SO4) to form carbon dioxide gas (CO2). Carbon dioxide gas, when passed through lime water [Ca(OH)2], turns it milky.
Explanation:
K2CO3 is formed from a weak acid, carbonic acid (H2CO3), and a strong base, potassium hydroxide (KOH). On hydrolysis, K2CO3 forms more OH- ions than H+ ions. Thus, it is basic, with a pH more than 7.
Explanation:
NH4Cl is formed from a weak base, ammonium hydroxide (NH4OH), and a strong acid, hydrochloric acid (HCl). On hydrolysis, NH4Cl forms more H+ ions than OH- ions. Thus, it is acidic, with a pH less than 7.
Explanation:
It is given that 10mL of a solution of NaOH is completely neutralised by 8mL of a solution of HCl. Hence, 20mL of the solution of NaOH, which is double the amount taken earlier, will require double the solution of HCl taken earlier, i.e., 16mL, to be completely neutralised.