IFIED 1m sarmy.mil/production/cninv000000000035487/course.html EXAM: General Che
ID: 538586 • Letter: I
Question
Explanation / Answer
Q.38) If a substance consists of only one type of atoms then it is an element. Element cannot be decomposed into simpler substances. So option 4 is the right answer.
Q. 39) The chemical name for H2SO4 is sulfuric acid. Option 2 is the right answer.
Q. 40) Oxidation-Reduction (redox) reaction is one in which one of the substate undergoes oxidation (reducing agent) and the other undergoes reduction (oxidising agent). In the following reaction the oxidation number all the species involved remains intact. So it is not a redox reaction, actually its a neutralization reaction. So option 5 is the answer.
Q.41) Acidic substances have pH<7, basic substances have pH>7 and for neural substances pH = 7. pH of blood is 7.4 which indicates that blood is slightly basic. answer is option 3.
Q. 42) Acid is a substance which prodes H+ ion when dissolved in water whereas base is a substance which produces OH- ion when dissolved in water. Acid and base react to form salt and water. (NH4)2SO4 is a salt, formed by the reaction between (NH4)2OH (base) and H2SO4 (acid). So option 3.
Q. 43) Oxidation of primary alcohol with potassium permanganate first gives an aldehde which undergoes further oxidation to give carboxylic acid. Here oxidation of propanol gives propanal (CH3CH2CHO) as the intermediate. Option 2 is the right answer.
Q. 44) An electrovalent bond (ionic bond) is formed by the complete transfer of elecron/s from one atom to another. The atom which loses the electron becomes positively charged (cation) and the other which gains the electron becomes negatively charged (anion). Answer is option 4.
Q.45) A coordinate covalent bond is a type of covalent bond in which both the shared pair of electrons come from a single atom and none from the other. answer is option 3.
Q.46) An atom is the smallest part of an element which cannot be further subdivided by chemical methods. An atom may or may not be stable. An atom shows all the properties of its parent element. Answer is option 1.
Q. 47) Endothermic reaction is one in which heat is absorbed. According to Le Chatelier's principle, when heat is supplied to an endothermic reaction it will proceed in the forward direction ie. rate of reaction increases. So answer is option 1.
Q. 48) ZnCO3 is zinc carbonate, H2SO4 is sulfuric acid, ZnSO4 is zinc sulfate, H2O is water and CO2 is carbon dioxide. Upward arrow indicates that CO2 is a gas and as a result it escapes. so option 1.
Q. 49) In this reaction the oxidation number of Fe (iron) increases from 0 to +3. Increase in oidation number is termed oxidation. Hence Fe undergoes oxidation. so option 1.
Q. 50) Calcium nitrate is chemically Ca(NO3)2. The molecular weight of it is 40 + 2(14 + 3 X 16) = 164. So the milligram molecular weight of calcium nitrate is 164 mg. Hence option 2.