Directions : Each of these questions contain two statements, Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.
Q.1. Assertion : Hard water is not suitable for laundry.
Reason : Soap containing sodium stearate reacts with hard water to precipitate out as calcium or magnesium
Q.2. Assertion : Hydrogen combines with other elements by losing, gaining or sharing of electrons.
Reason : Hydrogen forms electrovalent and covalent bonds with other elements.
Q.3. Assertion : Temporary hardness can be removed by boiling.
Reason : On boiling the soluble bicarbonates change to carbonates which being insoluble, get precipitated.
Q.4. Assertion : H+ does not exist freely and is always associated with other atoms or molecules.
Reason : Loss of the electron from hydrogen atom results in nucleus (H+) of ~ 1.5 × 10–3 pm size. This is
extremely small as compared to normal atomic and ionic sizes of 50 to 200 pm.
AnswerAnswer: (a) Due to extremely small size of H+ as compared to normal atomic and ionic size H+ does not exist freely.
Q.5. Assertion : Calgon is used for removing permanent hardness of water.
Reason : Calgon forms precipitates with Ca2+ and Mg2+.
Q.6. Assertion : H2O2 is not stored in glass bottles.
Reason : Alkali oxides present in glass catalyse the decomposition of H2O2
Q.7. Assertion : Decomposition of H2O2 is a disproportionation reaction.
Reason : H2O2 molecule simultaneously undergoes oxidation and reduction.