Author: Dr. Vikas Jasrotia

Questions on Acids Bases and Salts Class 10 (Answers) Questions on Acids Bases and Salts Class 10 (Answers) Ans 1. Curd contains lactic acid which can make poisonous compounds with brass and copper vessels. Ans 2. The fizzing will occur more vigorously in test tube ‘A’ because HCl is a strong acid and reacts faster than acetic acid which is a weak acid. Ans 3. (a) Highly soluble bases are called alkalies e.g., KOH. (b) Bee sting contains HCOOH, formic acid which causes irritation. Baking soda (basic) neutralises HCOOH, therefore it gives relief from pain by rubbing it on the…

Questions on Acids Bases and Salts Class 10 Questions on Acids Bases and Salts Class 10 Que 1. Curd is not kept in copper and brass utensils, why? Que 2. Equal lengths of magnesium ribbon 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’. In which test tube, will fizzing occur more vigorously and why? Que 3. (a) Write the name given to the bases that are highly soluble in water. Give an example. (b) Why does a bee sting cause pain…

Is Matter Around Us Pure Class 9 (Practice – 1 Answer) Is Matter Around Us Pure Class 9 Ans 1. The net movement of molecules from a region of high concentration to one of lower concentration. A spray of perfume or room freshener will get diffused into the air by which we can sense the odour. Ans 2. The matter has three states i.e Solid, Liquid, and Gases. Ans 3. The smell of hot sizzling food reaches you several meters away, but to get the smell of cold food, we have to go close because the kinetic energy of particles…

Is Matter Around Us Pure Questions (Practice) Que 1. Define diffusion with an example. Que 2. How many states of matter are there? Que 3. Give reasons for the following observation: The smell of hot sizzling food reaches you several metres away, but to get the smell of cold food, you have to go close. Que 4. Comment on the following statements: (a) Evaporation causes cooling. (b) Rate of evaporation of an aqueous solution decreases with an increase in humidity. (c) Sponge though compressible is solid. (d) Ice is solid at 0°C, while water is liquid at room temperature. (e)…

How to Find the Neutrons, electrons, and Protons Calculate the number of electrons, protons, and neutrons in the following species. (i) Phosphorus atom (ii) Phosphide ion (P3-) (iii) Magnesium ion (Mg2+) Mass number: P = 31, Mg = 24 Atomic numbers: P = 15, Mg = 12 (i) Phosphorus atom: Number of electrons = Atomic number = 15 Number of protons = Atomic number = 15 Number of neutrons = Mass number – atomic number = 31 – 15 = 13. (ii) Phosphide ion (P3-): Phosphide ion (P3-) = Phosphorus atom + 3 electrons P3- ≡ P + 3e- Thus,…

Value-Based Questions Class 11 Chemistry Chapter 7 According to Arrhenius’s theory, acids are substances that dissociate in water to give hydrogen ions H+ (aq) and bases are substances that produce hydroxyl ions OH – (aq). The ionization of an acid HX (aq) can be represented by the following equations: HX (aq) → H+ (aq) + X– (aq) or HX(aq) + H2O(l) → H3O + (aq) + X – (aq) Similarly, a base molecule like MOH ionizes in an aqueous solution according to the equation: MOH(aq) → M+ (aq) + OH– (aq) Bronsted acids are proton donors whereas Bronsted bases are…

Sample Paper Class 11 Chemistry This post contains a detailed syllabus for Class XI Chemistry along with a Solved Sample Paper for session 2022-2023 CBSE Class 11 Chemistry Detailed Syllabus Chapter I: Some Basic Concepts of Chemistry General Introduction: Importance and scope of Chemistry. Nature of matter, laws of chemical combination, Dalton’s atomic theory: the concept of elements, atoms, and molecules. Atomic and molecular masses, mole concept and molar mass, percentage composition, empirical and molecular formula, chemical reactions, stoichiometry, and calculations based on stoichiometry. Chapter II: Structure of Atom Discovery of Electron, Proton, Neutron, atomic number, isotopes, and isobars. Thomson’s…

Class 9 Science Chapter 2 Extra Questions and Answers Que 1. How can you convert a saturated solution to an unsaturated solution without adding any solvent to it? Ans 1. By heating a saturated solution, it becomes unsaturated. Que 2. Salt can be recovered from its solution by evaporation. Suggest some other technique for the same? Ans 2. The process of Crystallisation can be used to separate salt from its solution. Crystallisation is a separation technique used to separate a solid in a solution. The solution is warmed in an open container, allowing the solvent to evaporate, leaving a saturated…

CARBON AND ITS COMPOUNDS Carbon plays a very important role for all living beings. The amount of carbon in the earth’s crust is merely 0.02%, which is available in the form of minerals such as carbonates, hydrogen-carbonates, coal, and petroleum. The presence of carbon in the atmosphere of the earth is 0.03%, in the form of carbon dioxide. Almost all carbon compounds (except a few) are poor conductors of electricity. Two essential properties of Carbon are Catenation and tetravalency. Diamond and graphite both are formed by carbon atoms; however, the difference lies between them in the manner in which the carbon atoms…

Que. An element X (atomic number = 17) reacts with an element Y (atomic number = 20) to form a divalent halide. a) Where in the periodic table are elements X and Y placed? b) Classify X and Y metals, non-metals, or metalloids? c) What will be the Nature of the oxide of element Y? d) Draw the electron dot structure of the divalent halide. Ans. a) The electronic configuration of element X with atomic no. 17 is 2, 8, 7. Since it has 7 valence electrons, therefore, it lies in group 17(10 + 7), Since in element X third…