State one relevant observation for each of the following:
(a) To the copper nitrate solution, initially few drops of sodium hydroxide solution is added and then added in excess.
(b) Burning of ammonia in excess of oxygen.
(c) Dry ammonia gas is passed over heated PbO.
(a) A light-blue precipitate of copper(II) hydroxide is formed. It remains insoluble in excess sodium hydroxide solution.
(b) Ammonia burns with a greenish-yellow flame, forming nitrogen and water vapour.
(c) The buff-yellow lead(II) oxide is reduced to grey metallic lead.
More ICSE Moderate level questions
The following questions are pertaining to the laboratory preparation of Ammonia gas from Magnesium nitride: (a) Write a balanced chemical equation for its preparation. (b) Why is this method seldom used? (c) How do you identify the gas formed?
Complete and balance the following equations: (a) NH4Cl + Ca(OH)2 → (b) CuSO4 + NH4OH → (c) Cu + Conc. HNO3 →
State the terms/process for the following: (a) The energy released when an atom in the gaseous state accepts an electron to form an anion. (b) Tendency of an element to form chains of identical atoms. (c) The name of the process by which Ammonia is manufactured on a large scale. (d) A type of salt formed by partial replacement of hydroxyl radicals with an acid radical. (e) The ratio of the mass of a certain volume of gas to the same volume of hydrogen measured under the same conditions of temperature and pressure.
Fill in the blanks with the choices given in the brackets: (a) Metals are good ............... [oxidizing agents /reducing agents] (b) Non-polar covalent compounds are ............... [good / bad] conductors of heat and electricity. (c) Higher the pH value of a solution, the more is ............... [acidic / alkaline] it is. (d) ............... [Silver chloride / Lead chloride] is a white precipitate that is soluble in excess of Ammonium hydroxide solution. (e) Conversion of ethene to ethane is an example of ............... . [hydration / hydrogenation]
Identify the cation in each of the following cases: (a) Ammonium hydroxide solution when added to Solution B gives a white precipitate which does not dissolve in excess of ammonium hydroxide solution. (b) Sodium hydroxide solution when added to Solution C gives a white precipitate which is insoluble in excess of sodium hydroxide solution.
State a relevant reason for the following: [2] (a) Hydrogen chloride gas cannot be dried over quick lime. (b) Ammonia gas is not collected over water.
Rohit took two different salt solutions in test tubes C and D as shown in the figure below. He added dilute HCl to each of the two test tubes. The products formed in the test tubes C and D are silver chloride and lead chloride respectively. State: (a) one common observation made by Rohit in both the reactions. (b) the observations made by him on addition of excess of ammonium hydroxide to the products formed in: 1. test tube C 2. test tube D
Mohan has three solutions P, Q and R having a pH of 13, 5 and 2 respectively. Which of the above solutions P, Q or R: (a) will react with Magnesium to liberate hydrogen gas? (b) will liberate ammonia gas when it reacts with ammonium chloride? (c) will contain molecules as well as ions?
Complete and balance the following equations: (a) C2H4Br2 + KOH (alcoholic) ⟶ (b) NH3 (excess) + Cl2 ⟶ (c)
Give one significant observation when: (a) Barium chloride solution is added to zinc sulphate solution. (b) Lead nitrate is heated strongly. (c) Chlorine gas is passed through moist starch iodide paper.
Name the gas produced during each of the following reactions: (a) When copper is treated with hot, concentrated nitric acid. (b) When ammonia is burnt in an atmosphere of oxygen. (c) When ferrous sulphide reacts with dilute hydrochloric acid.
Study the following observations and name the anions present in each of the reactions. (a) When a crystalline solid 'P' is warmed with concentrated H2SO4 and copper turnings a reddish brown gas is released. (b) When few drops of dilute sulphuric acid is added to Salt 'R' and heated, a colourless gas is released which turns moist lead acetate paper silvery black. (c) When few drops of barium nitrate solution is added to the salt solution 'Q', a white precipitate is formed which is insoluble in HCl.
