Title 1. Basic Concepts of Chemistry (A _ R).pdf ✅

CHEMISTRY The following questions given below consist of an "Assertion" (A) and "Reason" (R) Type questions. Use the following Key to choose the appropriate answer. (A) If both (A) and (R) are true, and (R) is the correct explanation of (A). (B) If both (A) and (R) are true but (R) is not the correct explanation of (A). (C) If (A) is true but (R) is false. (D) If (A) is false but (R) is true. Q.1 Assertion : The number of O atoms in 16 g of oxygen and 16 g of ozone is same. Reason : Each of the species represent 1 g-atom of oxygen. [A] Sol. 16 g Oxygen  1 mole = 6.02 × 1023 Oxygen atoms 16 g Ozone  48 16 (= 3 1 mole of molecules)  3 × 3 1 Oxygen atoms = 6.02 × 1023 Oxygen atoms. Q.2 Assertion : 1 mole of sulphuric acid contains 32 g each of sulphur and oxygen element. Reason : 1 mole of sulphuric acid represents 98 g of the species. [D] Sol. 1 mole H2SO4  2 g H + 32 g S + 64 g O  98 g H2SO4. Q.3 Assertion : 1 mole of H2SO4 is neutralised by 2 moles of NaOH but 1 equivalent of H2SO4 is neuralised by 1 equivalent of NaOH. Reason : Equivalent wt. of H2SO4 is half of its moleculer wt. while equivalent wt. of NaOH is 40. [B] 16 Jun 2009 __________(Ex. Sheet)________________ Q.4 Assertion : 1 Avogram is equal to 10 amu. Reason : Avogram is reciprocal of Avogadro number. [D] Q.5 Assertion : The ash produced by burning Mg in air is lighther than the original mass of Mg. Reason : Mg burns in air to produce MgO2 and Mg3N2 [D] Q.6 Assertion : Vapour density of sulphur vapour relative to oxygen is 2 because sulphur atom is twice as heavy as that of O atom. Reason : Vapour density depends upon the molecular state of the substance in solid state. [D] Q.7 Assertion : Equal volumes of all the gases contain equal number of atoms. Reason : Atom is the smallest particle which takes part in chemical reactions. [D] 17 Jun 09_____________________________________ Q.8 Assertion : The ratio by volume of gaseous reactants and products is in agreement with their molar ratio. Reason : Volume of a gas is inversely proportional to the number of moles of a gas.[C] Q.9 Assertion : One mole of SO2 contains double the number of molecules present in one mole of O2. Reason : Molecular weight of SO2 is double to that of O2. [D] Q.10 Assertion : The compounds NaCl and CaO do not exists as discrete molecules. Reason : For a substance that does not exist as discrete molecules, the formula weight and the molecular weight are identical. [B] Q.11 Statement-1 : Molarity of pure water is 55.5 M. Statement-2 : Molarity is temperature dependent parameter. [B] Q.12 Statement-1 : 1 g-atom of sulphur contains Avogadro number of sulphur molecules Statement-2 : Atomicity of sulphur is eight. [D] Q.13 Statement-1 : The number of O atoms in 1 gm. of O2 , 1 gm O3 and 1 gm of atomic oxygen is same. Statement-2 : Each of the species represents 1/16 gm-atom of oxygen. [A] Q.14 Statement-1 : The ratio by volume of H2 : Cl2 : HCl in a reaction H2(g) + Cl2(g) → 2HCl(g) is 1 : 1 : 2.