Metals and Non-Metals Previous Years Questions : Solutions Show the formation of Na2O by the transfer of electrons. [CBSE 2019] [2 Marks]Sol: Show the formation of magnesium oxide by the transfer of electrons. [CBSE 2019] [2 Marks]Sol: What are ionic compounds ? Why do ionic compounds not conduct electricity in the solid state? [CBSE 2019] [2 Marks]Sol:The compound […]
Acids, Bases and Salts Previous Years Questions : Solutions If 10 ml of H2SO4 is mixed with 10 ml of Mg(OH)2 of the same concentration, the resultant solution will give the following colour with universal indicator: [1 Mark] [CBSE 2020] Red Yellow Green BlueSol:The Correct option is (c) Green 2 mL of sodium hydroxide is added to a […]
Periodic Classification of Elements Important Questions “Atomic number of an element is considered to be a more appropriate parameter than its atomic mass for a chemist.” Take the example of element X (atomic number 13) to justify this statement. How many triads did Dobereiner identify from the existing elements during his time ? Give an […]
Periodic Classification of Elements Notes Döbereiner’s triads:- Dobereiner arranged elements with similar properties into groups having three elements each and called those groups triads.When the three elements in a triad were written in the order of increasing atomic masses, the atomic mass of middle element was roughly equal to the average atomic masses of other […]
Atoms and Molecules Notes Laws of chemical combination:- Law of conservation of mass:- It states that mass can neither be created nor be destroyed in a chemical reaction. Or,It states that the total mass of reactants is equal to total mass of products in a chemical reaction. Law of constant proportion:- It states that in […]
Carbon and its Compounds Previous Years Questions Assertion (A) : Melting point and boiling point of ethanol are lower than that of sodium chloride. Reason (R) : The force of attraction between the molecules of ionic compounds are very strong. Answer the question selecting appropriate options given below : a. Both Assertion (A) and Reason […]
Carbon and its Compounds Important Questions a. Complete the following equations:-b. Write the name of the following:-i. CH3CH2COOHii. CH3CH2Brc. Draw the electron dot structure of ethene (C2H4). a. Name the compound CH3CH2OH and identity its functional group.b. Give a chemical test to distinguish between ethanol and ethanoic acid.c. Name the product formed when an organic […]
Carbon And Its Compounds – Notes Covalent compound:- The compound formed by the sharing of electrons between the atoms is known as covalent compound. Difference between covalent compound and ionic/electrovalent compounds:- No. Covalent compounds Ionic/Electrovalent compounds (i) Covalent compounds are formed by the sharing of electrons between atoms. Ionic compounds are formed by the transfer […]
Metal and Non-Metals Important Questions In what forms are metals found in nature? With the help of examples explain how metals react with oxygen, water and dilute acids. Also write chemical equations for the reactions. How is copper obtained from its ore (Cu2S)? Write only the chemical equations. How is copper thus obtained refined? Name […]
Metals And Non-Metals : Previous Years Questions Metal oxide generally reacts with acids, but few oxides of metals also react with bases, such metallic oxides are : MgO ZnO Al2O3 CaOa. 1 and 2 b. 2 and 3c. 3 and 4 d. 1 and 4 [1 mark] [CBSE 2023] Bronze is an alloy of a. […]