Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer.
Answer: The pH value of Basic solution is greater than 7. Neutral solution is equal to 7. Acidic solution is... View Article
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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: Acetic acid is a weak acid, while HCl is a strong acid. The formation of hydrogen gas as a... View Article
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 (a) neutral? (b) Strongly alkaline? (c) Strongly acidic? (d) Weakly acidic? (e) Weakly alkaline?
Answer: pH is defined as the negative logarithm of H+ ion concentration. Hence, the meaning of the name pH is... View Article
Why do acids not show acidic behaviour in the absence of water?
Answer: An acid is any hydrogen-containing substance that is capable of donating a proton or hydrogen ion to another substance.... View Article
Compounds such as alcohols and glucose also contain hydrogen but are not categorised as acids. Describe an Activity to prove it
Answer: Acids are substances that produce hydrogen ions as they dissociate with water. As some compounds dissociate in aqueous solution,... View Article
Write word equations and then balanced equations for the reaction taking place when (a) Dilute sulphuric acid reacts with zinc granules. (b) Dilute hydrochloric acid reacts with magnesium ribbon. (c) Dilute sulphuric acid reacts with aluminium powder. (d) Dilute hydrochloric acid reacts with iron filings.
Answer: The representation of a chemical reaction in the form of substances is known as a chemical equation. The equation... View Article
Which one of the following types of medicines is used for treating indigestion? (a) Antibiotic (b) Analgesic (c) Antacid (d) Antiseptic
Answer: (c) Antacid Because of the presence of HCl, the pH of our digestive system is acidic. Antacids are bases... View Article
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 (the same solution as before) required to neutralise it will be (a) 4 mL (b) 8 mL (c) 12 mL (d) 16 mL
Answer: (d) 16 mL Since 10 ml of NaOH requires 8 mL of HCl. 20 ml of NaOH require_______HCl. Let... View Article
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
Answer: (b) HCl The eggshell contains calcium carbonate, which on reaction with HCl liberates CO2 gas which turn lime water to... View Article
What will happen if a solution of sodium hydrocarbonate is heated? Give the equation of the reaction involved.
Answer: Sodium Hydrogen Carbonate also known as Sodium Bicarbonate or Baking Soda. It is a crystalline solid white which has... View Article
Name the substance which on treatment with chlorine yields bleaching powder
Answer: Calcium hydroxide is the material that produces bleaching powder when introduced to chlorine. Bleaching powder The chemical name of... View Article
Do basic solutions also have H+(aq) ions? If yes, then why are these basic?
Answer: Bases are substances to release hydroxide ions (OH– ions) when dissolved in water. They are found to have a... View Article
What effect does the concentration of H+(aq) ions have on the nature of the solution?
Answer: The nature of the solution is determined by the concentration of hydrogen ions. If the concentration of hydrogen ions... View Article
You have two solutions, A and B. The pH of solution A is 6 and pH of solution B is 8. Which solution has more hydrogen ion concentration? Which of this is acidic and which one is basic?
Answer: pH is defined as the negative logarithm of H+ ion concentration. Hence, the meaning of the name pH is... View Article
How is the concentration of hydroxide ions (OH–) affected when excess base is dissolved in a solution of sodium hydroxide?
Answer: When a base is dissolved in sodium hydroxide solution, the number of hydroxide ions increases, but it eventually reaches... View Article
How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted?
Answer: As acid is added to water, a certain amount of hydronium will be present in a certain volume of... View Article
While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?
Answer: The reaction of acid and water is an exothermic reaction since a lot of heat is liberated during the... View Article
Why does dry HCl gas not change the colour of the dry litmus paper?
Answer: It does not dissociate into H+ ions when dry HCL is used. Only in aqueous solution can acids dissociate... View Article
Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Answer: Acids are substances that produce hydrogen ions as they dissociate with water. As some compounds dissociate in aqueous solution,... View Article
Which gas is usually liberated when an acid reacts with a metal? Illustrate with an example. How will you test for the presence of this gas?
Answer: As acid reacts with metal, hydrogen gas is released. A formation of gas bubbles has been observed along the... View Article
