InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 51. |
What similarity is found in the electronic configurations of hydrogen and halogen? |
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Answer» Both hydrogen and halogen are in short of one electron for the completion of the outermost orbital containing electrons. |
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| 52. |
LiCl and MgCk dissolve in alcohol. How do you explain this? |
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Answer» Both LiCl and MgCl2 are covalent compounds and dissolve in alcohol. This is due to high polarizing power of Li+ and Mg2+ ions. |
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| 53. |
Why alkaline earth metals are weaker reducing agents than alkali metals? |
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Answer» Alkaline earth metals are higher due to the completely filled orbitals than alkali metals. |
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| 54. |
Which of the following alkaline earth metal is most stable to heat ?(a) MgCOg(b) CaCOg(c) SrCOg(d) BaCOg |
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Answer» The answer is (d) BaCOg |
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| 55. |
Which of the following compound is obtained as a bye-product in Solvay Ammonia Process ?(a) Carbon dioxide(b) Ammonia(c) Calcium chloride(d) Calcium carbonate |
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Answer» (c) Calcium chloride |
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| 56. |
Name the compound which can be obtained by Solvay‘s process. |
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Answer» Sodium carbonate |
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| 57. |
Why K2CO3 cannot be prepared by Solvay process? |
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Answer» Solvay process is not applicable for the preparation of potassium carbonate because potassium bicarbonate is soluble in water and it doesn‘t precipitates out like sodium bicarbonate. |
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| 58. |
What is milk of lime ? |
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Answer» A suspension of slaked lime in water is known as milk of lime. |
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| 59. |
Give chemical reaction when:Calcium nitrate is heated. |
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Answer» Calcium nitrate, when heated, undergoes decomposition to form calcium oxide. 2Ca(NO3)2(s) → 2CaO(s) + 4NO2(g) + O2(g) |
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| 60. |
How does milk of lime reacts with chlorine? Write the chemical reaction. |
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Answer» Milk of lime reacts with chlorine to form bleaching powder. 2 Ca(OH)2+Cl2 → CaCl2 + Ca(OCl)2 +2H2O |
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| 61. |
Give chemical reaction when:Chlorine reacts with slaked lime. |
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Answer» Bleaching powder is formed when chlorine is made to react with slaked lime. Ca(OH)2 + Cl2 → CaOCl2 + H2O |
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| 62. |
Give one important use of following compounds. 1. NaHCO3 2. Slaked lime 3. NaOH |
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Answer» 1. Sodium bicarbonate is used as antacid 2. Slaked lime is used for white washing, 3. NaOH is used in manufacture of soap. |
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| 63. |
What is effect of heat on the following compounds? (Give equations for the reactions) (i) CaCO3 (ii) CaSO42H2O |
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Answer» (i) CaCO3 \(\overset{heat}{\longrightarrow}\) CaO + CO2 (decomposition/calcinations) (ii) 2CaSO4.2H2O \(\overset{heat}{\underset{strongly}{\longrightarrow}}\) (CaSO4) (Dead buront plaster)(Plaster of paris) + 2H2O + 3H2O |
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| 64. |
Why are alkali metals not found in nature? |
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Answer» Sodium, cesium, lithium, francium, potassium, rubidium all together comprises of alkali metals. they consist of only one electron on its valence shell, which gets loosed easily due to their low ionization enthalpy. |
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| 65. |
Why group 2 elements (Mg and Ca) are harder and denser than group 1 elements? |
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Answer» They have strong metallic bonds due to smaller size and have more number of valence electrons. |
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| 66. |
Calculate the oxidation state of Na in Na2O2. |
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Answer» Let, the oxidation state of Na = x |
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| 67. |
Why are alkali metals strong reducing agents? |
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Answer» It is because of low ionisation energy. They can lose electrons easily, that is why they are strong reducing agents. |
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| 68. |
Why is potassium more reactive than sodium? |
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Answer» K has lower ionisation energy than sodium due to bigger atomic size, therefore, it is more reactive. |
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| 69. |
Explain the following:BeO is insoluble in water while BeSO4 is water soluble. |
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Answer» The sizes of Be2+ and O2- are small and are highly compatible with each other. Due to this, a high amount of lattice energy is released during its formation. The hydration energy, when it is made to dissolve in water, is not enough to overcome the lattice energy. Thus, BeO is barely soluble in water. Whereas the size of an SO42- is large compared to Be2+ and there is lesser compatibility and lattice energy which can be easily overcome by the hydration energy. Thus, BeSO4 is easily soluble in water. |
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| 70. |
Explain the following:Sodium carbonate solution is alkaline. |
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Answer» Sodium carbonate is a salt of strong base and weak acid so it on hydrolysis gives NaOH which is a strong base so Sodium carbonate solution is alkaline. |
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| 71. |
What is used for drying alcohol and non-acidic gases and why? |
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Answer» Calcium is used for drying alcohol and non-acidic gases because Ca does not react with alcohol. |
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| 72. |
Complete the following equations : (i) Ca + N2 → (ii) Ca + SO2 → (iii) Ca(OH)2 + NH4Cl → (iv) Ca + CO2 → |
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Answer» (i) 3Ca + N2 → Ca3N2 (ii) 2Ca + SO2 → 2CaO + S (iii) Ca(OH)2 + 2NH4Cl \(\overset{heat}{\longrightarrow}\) CaCl2 + 2H2O + 2NH3 (iv) 2Ca + CO2 → CaO + C |
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| 73. |
Complete the following 1. Ca + H2O → 2. Ca(OH)2 + Cl2 → 3. BeO + NaOH → |
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Answer» 1. Ca + H2O → CaO + H2O 2. Ca(OH)2 + Cl2 → CaOCl2 + H2O 3. BeO + NaOH → Be(OH)2 + Na2O |
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| 74. |
The second ionization enthalpy of Ca is higher than first and yet calcium forms CaCl2 and not CaCl Why? |
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Answer» The hydration energy of Ca2+ over comes the second ionization energy of Ca, that is why Ca forms CaCl2 and not CaCl. Ca+ is not stable. |
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| 75. |
What is quick lime? What happens when we add water to it? |
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Answer» Ca O is quick lime. When we add water to it slaked limes Ca (OH)2 is formed. |
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| 76. |
Why does ionisation energy of alkali metals decrease with the increase in atomic number? |
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Answer» Atomic size increases with increase in atomic number, therefore, nuclear force of attraction between valence electrons and nucleus decreases, hence ionisation energy decreases down the group. |
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| 77. |
Why do alkali metals have low ionisation energy? |
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Answer» It is due to largest atomic size, they can lose electrons easily. |
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| 78. |
The alkali metals have no tendency to show variable oxidation states. Give reason. |
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Answer» Alkali metals show oxidation state of +1. With the loss of valence electron it attains the stable configuration of nearest inert gas. Its second ionization potential is high. Hence an alkali metal does not show variable oxidation states. |
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| 79. |
Why are group 1 elements called alkali metals? |
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Answer» It is because their hydroxides are soluble bases called alkalies. Secondly their ashes are alkaline in nature. |
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| 80. |
Write the alkali metals in the increasing order of hydration energy. |
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Answer» Li+ > Ma+ > K+ > > Rb+ > Cs+ |
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| 81. |
Which alkali metal ion forms largest hydrate ion in aqueous solution and why? |
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Answer» Li+ forms largest hydrated cations because it has highest hydration energy. It has smallest size therefore, it is most hydrated. |
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| 82. |
Heat of Hydration of Na+ (size 102 pm) = -397 kJ mol-1 whereas Caz 100 pm) = -1650 kJ mol-1. Explain the difference. |
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Answer» Ca2+ is smaller in size than Na+ and also it has higher charge, therefore, its hydration energy is more than that of Na+. |
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| 83. |
Why is sodium thiosulphate used in photography? |
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Answer» Because of its complex forming behaviour. |
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| 84. |
What is the reason that sodium reacts with water more vigorously than lithium? |
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Answer» Because sodium is more electropositive. |
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| 85. |
Which of the following do not give flame test ?(a) Be(b) K(c) Sr(d) Na |
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Answer» The answer is (a) Be |
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| 86. |
Which of the following metal has lowest melting point ?(a) Na(b) K(c) Rb(d) Cs |
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Answer» The answer is (d) Cs |
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| 87. |
Amongst Li, Na, K, RB, Cs, Fr which one has highest and which one has the lowest ionisation enthalpy? |
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Answer» Li has highest and Fr has lowest ionization enthalpy. |
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| 88. |
Which of the alkali metals halides have lowest lattice energy ?(a) LiF(b) NaCl(c) KBr(d) Csl |
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Answer» The answer is (d) Csl |
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| 89. |
Name the reagent or one process to distinguish between: 1. BeSO4 and BaSO4 2. Be(OH2) and Ba(OH)2 |
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Answer» 1. BeSO4 is soluble in water while BaSO4 is not. 2. Be(OH)2 dissolves in NaOH while Ba(OH)2 is insoluble. |
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| 90. |
Why second ionization energy of group 2 elements is less than group 1 elements? |
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Answer» Second ionization energy of group 2 elements is less than group 1 elements because more energy is required to release second electron from alkali metals. i.e. group 1 metal ions. |
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| 91. |
Why is oxidation state of Na and K always + 1? |
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Answer» It is due to their high second ionization enthalpy and stability of their ions [Na+ K+] |
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| 92. |
Name the elements present in Group 2. |
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Answer» Beryllium, Magnesium, Calcium, Strontium, Barium and Radium. |
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| 93. |
Why is oxidation state of Na and K always +1? |
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Answer» It is due their high second ionization enthalpy and stability of their ions [Na+,K+]. |
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| 94. |
Why do group I elements have lowest ionization enthalpy? |
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Answer» Because of their largest size in their respective periods, solitary electron present in the valence shell can be removed by supplying small amount of energy. |
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| 95. |
The atomic radii of alkaline earth metals are smaller than those of the corresponding alkali metals. Explain why? |
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Answer» The atomic and ionic radii of the alkaline earth metals are smaller than those of the corresponding alkali metals in the same period because of the increased nuclear charge in there elements. |
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| 96. |
Why do alkaline earth metals have low ionization enthalpy? |
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Answer» The alkaline earth metals have low iodization enthalpies due to fairly large size of atoms. |
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| 97. |
The second ionization enthalpy of calcium is more than the first. How is that calcium forms CaCl2 and not CaCl give reasons. |
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Answer» The higher value of second ionization enthalpy is more than compensated by the higher enthalpy of hydration of Ca2+. Therefore formation of CaCl2 becomes more favorable than CaCl energetically. |
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| 98. |
Explain the following:The solution of alkali metals in liquid ammonia is blue in colour. |
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Answer» The alkali metals dissolve in liquid ammonia giving deep blue solutions M +(x +y)NH3= [M(NH3 )x ]+ + [e (NH3 )y ]- The blue colour of the solution is due to the ammoniated electron which absorbs energy in the visible region of light and thus imparts blue colour to the solution. |
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| 99. |
What is responsible for the blue colour of the solution of alkali metal in liquid ammonia? Give chemical equation also. |
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Answer» The solvated electron, [e(NH3)]– or ammoniated electron is responsible for blue colour of alkali metal solution in NH3. It absorbs light from visible region and radiates complementary colour, (in the equation am = ammoniated) Na+(am) + e–(am) + NH2(l) → NaNH2(am) + \(\frac{1}{2}\)H2(g) |
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| 100. |
When CO2 gas is passed in lime water it turns milky but in case of excess CO2, milkiness disappeard. Support the statement by giving suitable reaction equations. |
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Answer» When CO2 gas is passed in lime water, it turns milky due to the formation of calcium carbonate. Ca(OH)2 + CO2 → CaCO3 + H2O On passing excess of CO2, milkiness disappears because the precipitate dissolves to form calcium hydrogen carbonate. CaCO3 + CO2 + H2O → Ca(HCO3)2 |
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