NCERT
- is a poor conductor of heat. Mercury and Lead 2
- is the best conductor of heat. Silver is answer 2
- can be easily cut with a knife. Sodium is answer 2
- is a liquid at room temperature. Mercury is the answer 2
- Give two important uses of washing soda and baking soda wo important uses of washing soda are: → It is used in glass, soap, and paper industries. → It is used to remove permanent hardness of water... 1
- What is a neutralization reaction? Give two examples. A reaction in which an acid and base react with each other to give a salt and water is termed as neutralization reaction.For Example: (i) Na... 1
- Plaster of Paris should be stored in a moisture-proof container. Explain why? Plaster of Paris should be stored in a moisture-proof container because the presence of moisture (or water) can cause its slow setting by br... 1
- A milkman adds a very small amount of baking soda to fresh milk. (a) Why does he shift the (a) The milkman shifts the pH of the fresh milk from 6 to slightly alkaline because in alkaline condition, milk does not set as curd easily.... 1
- Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain your answer. The pH of milk is 6. As it changes to curd, the pH will reduce because curd is acidic in nature. The acids present in it decrease the pH. 1
- Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A The fizzing will occur strongly in test tube A, in which hydrochloric acid (HCl) is added. This is because HCl is a stronger acid than CH₃CO... 1
- Five solutions A, B, C, D and E when tested with universal indicator showed pH (a) Neutral →Solution D with pH 7 (b) Strongly alkaline →Solution C with pH 11 (c) Strongly acidic →Solution B with pH 1 (d) Weakly acidic →... 1
- Why do acids not show acidic behaviour in the absence of water? Acids do not show acidic behaviour in the absence of water because the dissociation of hydrogen ions from an acid occurs in the presence of... 1
- Why does distilled water not conduct electricity, whereas rain water does? Distilled water cannot conduct electricity because it does not contain ions while rain water conducts electricity as it contains ions due pr... 1
- Compounds such as alcohols and glucose also contain hydrogen but are not categorized Two nails are fitted on a cork and are kept it in a 100 mL beaker. The nails are then connected to the two terminals of a 6-volt battery thr... 1
- Write word equations and then balanced equations for the reaction taking place when (a) H₂SO₄ (aq) + Zn (s) → ZnSO₄ (aq) + H₂ (g) (b) 2HCl (aq) + Mg (s) → MgCl₂ (aq) + H₂ (g) (c) 3H₂SO₄ (aq) + 2Al (s) → Al₂(SO₄)₃ (aq) + 3H₂... 2
- Which one of the following types of medicines is used for treating indigestion? (a) Antibiotic Correct option is (c) Antacid 2
- 10 mL of a solution of NaOH is found to be completely neutralised by 8 mL of a given solution of HCl. Correct option is (d) 16 mL 2
- A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. Correct option is (b) HCl 2
- A solution turns red litmus blue, its pH is likely to be (a) 1 (b) 4 (c) 5 (d) 10 Correct option is (d) 10 2
- Write an equation to show the reaction between Plaster of Paris and water. Plaster of Paris (CaSO₄. 1/2H₂O) on mixing with water, changes into gypsum (CaSO_(4 )2H₂O), which sets to a hard mass in about half an hour.... 2
- What will happen if a solution of sodium hydrocarbonate is heated? When sodium hydrogen carbonate is heated then sodium carbonate and water is formed along with the evolution of carbon dioxide gas. 2NaHCO₃→... 1
- Name the sodium compound which is used for softening hard water. Washing soda (Na₂CO₃.10H₂O) 2
- Name the substance which on treatment with chlorine yields bleaching powder? Calcium hydroxide [Ca(OH)₂] 2
- What is the common name of the compound CaOCl2? Bleaching Powder 2