208 + Interview Questions in THE-ALKALI-METALS IN GENERAL AWARENESS Page 3 InterviewSolution

101.	Which of the following is monovalent ?A. Alkali metalsB. Alkaline earth metalsC. MetalloidsD. Metals.
Answer» Correct Answer - A Alkali metals are monovalent.

Discussion

102.	Lithium shows diagonal relationship withA. MagnesiumB. BerylliumC. AluminiumD. Boron.
Answer» Correct Answer - A Lithium shows diagonal relationship with magnesium.

Discussion

103.	How does the ionisation energy of 1st group elements very ?A. increases down the groupB. decreases down the groupC. remain unchangedD. variation is not regular.
Answer» Correct Answer - B Ionization energy among the 1st group elements decreases down the group.

Discussion

104.	Which of the following is not a white crystalline solid ?A. `LiHCO_(3)`B. `NaHCO_(3)`C. `KHCO_(3)`D. `CsHCO_(3)`.
Answer» Correct Answer - A `LiHCO_(3)` does not exist in solid state.

Discussion

105.	Which of the following statement is not true to explain that first member in a group differs in many respects from other members of its group ?A. Small sizeB. High electronegativityC. Nonavailability of d-orbitals for bondingD. Similar ionic charges.
Answer» Correct Answer - D See Comprehensive Review.

Discussion

106.	Microcosmic salt isA. `Na(NH_(4))HPO_(4).4H_(2)O`B. `Na(NH_(4)).H_(2)O`C. `Na(NH_(3))HPO_(4). 4H_(2)O`D. `K(NH_(4))HPO_(3).2H_(2)O`
Answer» Correct Answer - A Microcosmic salt is `Na(NH_(4))HPO_(4).4H_(2)O`

Discussion

107.	Most insoluble salt of Li in water isA. `Li_(2)CO_(3)`B. `Li_(2)SO_(4)`C. `Li_(3)PO_(4)`D. LiF.
Answer» Correct Answer - C `Li_(3)PO_(4)` is the most insoluble salt of Li in water.

Discussion

108.	Sodium ordinarily does not show an oxidation state of `+2`, because of itsA. high first ionization energyB. high second ionization energyC. large ionic radiusD. high electronegativity.
Answer» Correct Answer - B See Comprehensive Review.

Discussion

109.	The most insoluble salt of sodium isA. `Na_(4)[Fe(CN)_(6)]`B. `Na_(3)[Fe(CN)_(6)]`C. `Na[Sb(OH)_(6)]`D. `Na[Fe(CN_(5))NO].2H_(2)O`.
Answer» Correct Answer - C One of the most insoluble salt of sodium in water is `Na[Sb(OH)_(6)]` or sodium hexahydroantimonate (V). The corresponding potassium salt is more soluble in water. It is used to detect the presence of `Na^(+)` ions.

Discussion

110.	A colloidal solution of Na in ether isA. golden yellow in colourB. blue in colourC. colourlessD. violet in colour.
Answer» Correct Answer - D A colloidal solution of Na in ether is violet coloured.

Discussion

111.	Which of the following has lowest thermal stability ?A. `Li_(2)CO_(3)`B. `Na_(2)CO_(3)`C. `K_(2)CO_(3)`D. `Rb_(2)CO_(3)`.
Answer» Correct Answer - A Only alkali metal carbonate, which decompose on heating is `Li_(2)CO_(3)`. `Li_(2)CO_(3)rarroverset(Delta)rarrLi_(2)O+CO_(2)uarr`

Discussion

112.	The alkali metalsA. forms salt like hydridesB. form salts which are predominantly covalentC. show decreased chemical reactivity with dry oxygen in going from Li to CsD. show increasing electronegativity from Li to Cs.
Answer» Correct Answer - A Alkali metals form salt like hydrides.

Discussion

113.	Caesium forms chiefly ionic compounds becauseA. the valence electrons are poorly bound to the nucleusB. its electronegativity is very highC. its ionization energy is very lowD. the polarizablitiy of the cation is high.
Answer» Correct Answer - C See Comprehensive Review (properties).

Discussion

114.	Caesium oxide will beA. AcidicB. BasicC. Weakly basicD. Amphoteric.
Answer» Correct Answer - B Alkali metal oxides are basic in character due to low I.E.

Discussion

115.	Caesium oxide will beA. very strongly basicB. acidicC. Weakly basicD. Amphoteric.
Answer» Correct Answer - A CsO will be strongly basic (All alkali metal oxides are strongly basic).

Discussion

116.	Sodium when dropped in water catches fire becauseA. it has higher atomic massB. it is a metalC. it is highly electropositive is natureD. the hydrogen gas evolved in the reaction is combustible in nature.
Answer» Correct Answer - D `Na+H_(2)OrarrNaOH+1//2H_(2)`. As the reaction is highly exothermic therefore hydrogen evolved catches fire.

Discussion

117.	Which one of the following alkali metals emit light of longest wavelength in the flame test ?A. NaB. LiC. KD. Cs.
Answer» Correct Answer - B It is due to high I.E. of Li it absorbs blue colour and emits red colour (larger wavelength).

Discussion

118.	`Li_(2)O_(2)` is formed whenA. Li is heated strongly in excess of airB. LiOH is heated in an atmosphere of `O_(2)`C. `H_(2)O_(2)` and alcohol are added to a solution of LiOH in waterD. None of these.
Answer» Correct Answer - C `Li_(2)O_(2)` is formed from LiOH and `H_(2)O_(2)` `2LiOH + 2H_(2)O_(2)+H_(2)OrarrLi_(2)O_(2).H_(2)O_(2).3H_(2)O`

Discussion

119.	Which of the following properties is not true for an alkali metal ?A. Low atomic volumeB. Low ionization energyC. Low densityD. Low electronegativity.
Answer» Correct Answer - A Alkali metals have large atomic volumes due to low densities `=("Atomic mass")/("Density of element in solid state at its melting pt.")`

Discussion

120.	Sodium nitrate decomposes above `800^(@)C` to giveA. `N_(2)`B. `O_(2)`C. `NO_(2)`D. `Na_(2)O`.
Answer» Correct Answer - B `NaNO_(3)` decomposes above `800^(@)C` to give `O_(2)` `2KNO_(3)(s)overset(800^(@)C)rarr2KNO_(2)(s)+O_(2)(g)`

Discussion

121.	Which of the following decomposes on heating ?A. LiOHB. NaOHC. KOHD. CsOH.
Answer» Correct Answer - A `2LiOHrarrLi_(2)O+H_(2)O`. Lithium hydroxide decomposes because it gives a stable oxide `(Li_(2)O)`.

Discussion

122.	Which of the following is correct ?A. In the Castner process of sodium extraction, NaCl is used as an electrolyteB. Sodium reduces `CO_(2)` to carbonC. Magnesium reacts with cold water and liberates hydrogenD. Magnallium is one alloy of Mg and zinc.
Answer» Correct Answer - B `2Na+CO_(2)rarrNa_(2)O_(2)+C`

Discussion

123.	Chill salt petre isA. `NaNO_(3)`B. `Na_(2)SO_(4)`C. `KNO_(3)`D. `OH^(-)`
Answer» Correct Answer - A Chile saltpeter is `NaNO_(3)`.

Discussion

124.	Which out of the following compounds is the most stable ?A. LiClB. LiFC. LiBrD. LiI.
Answer» Correct Answer - B It has a strong ionic bond.

Discussion

125.	The fusion mixture is a mixture ofA. `K_(2)CO_(3)+Na_(2)CO_(3)`B. `KHSO_(4)+NaHSO_(4)`C. `K_(2)CO_(3)+NaHSO_(4)`D. `KHSO_(4)+Na_(2)SO_(3)`
Answer» Correct Answer - A Fusion mixture is `Na_(2)CO_(3) + K_(2)CO_(3)`.

Discussion

126.	Excess of `Na^(+)` ions in our system causesA. DiabetesB. AnaemiaC. Low blood pressureD. High blood pressure.
Answer» Correct Answer - D Excess of `Na^(+)` in human system causes high blood pressure.

Discussion

127.	`LiAlH_(4)` is obtained by reacting an excess of…. With an ethereal solution of `AlCl_(3)`A. LiClB. LiHC. LiD. LiOH.
Answer» Correct Answer - B `4LiH+AlCl_(3)overset("either")rarrLiAlH_(4)+3LiCl`

Discussion

128.	The correct sequence of the alkali metals in the group isA. Fr, Na, K, Rb, Cs, LiB. Li, Na, K, Rb, Cs, FrC. Na, K, Rb, Cs, Fr, LiD. Rb, Cs, Li, Na, K.
Answer» Correct Answer - B Correct sequence of alkali metals down the group is Li, Na, K, Rb, Cs, Fr.

Discussion

129.	Alkali metals have very small value of electronegativity. The electronegativity down the groupA. increasesB. decreasesC. remains sameD. none of these.
Answer» Correct Answer - B The size increases and therefore the electronegativity decreases.

Discussion

130.	Assertion (A) `underset(CH)overset(C)("\|\|\|")+2Lioverset(NH_(3)(i))rarrunderset(CLi)overset(CLi)("\|\|\|")+H_(2)` Reasons (A) Alkali metals form acetylides with terminal alkynes.
Answer» Correct Answer - D Li does not form acetylides.

Discussion

131.	Which of the following alkali metal halides has the lowest lattice energy ?A. LiFB. NaClC. KBrD. CsI.
Answer» Correct Answer - D Lattice energy depends on size of atoms. Cs has a large size and therefore its lattice energy is less.

Discussion

132.	Alkali metals in each period haveA. Smallest sizeB. Lowest ionization energyC. Highest electron affinityD. Highest electronegativity.
Answer» Correct Answer - B See Comprehensive Review.

Discussion

133.	Which among the following is most soluble in alcohol ?A. `CsClO_(4)`B. `LiClO_(4)`C. `KClO_(4)`D. `NaClO_(4)`.
Answer» Correct Answer - B `LiClO_(4)` is extremely soluble in alcohol.

Discussion

134.	The largest ionic radii in water is ofA. `K^(+)`B. `Cs^(+)`C. `Na^(+)`D. `Li^(+)`.
Answer» Correct Answer - D Smaller the size more is the hydration and hence larger is the effective ionic size in aqueous solution.

Discussion

135.	When `CO_(2)` is bubbled into an aqueous solution of `Na_(2)CO_(3)` the following is formedA. `NaOH`B. `NaHCO_(3)`C. `H_(2)O`D. `OH^(-)`
Answer» Correct Answer - B `Na_(2)CO_(3)(aq)+H_(2)O(l)+CO_(2)(g)rarr2NaHCO_(3)(aq)`.

Discussion

136.	Which of the following is radioactive ?A. `Na^(23)`B. `K^(39)`C. `K^(40)`D. `Ca^(40)`
Answer» Correct Answer - C `._(19)K^(40)` is radioactive in nature.

Discussion

137.	Which of the following is a man made element ?A. RaB. FrC. RnD. Lr.
Answer» Correct Answer - B Francium is a man made element.

Discussion

138.	Which one of the these is basic ?A. `CO_(2)`B. `SiO_(2)`C. `Na_(2)O`D. `SO_(2)`
Answer» Correct Answer - C Alkali metal oxides (e.g. `Na_(2)O`) are most basic.

Discussion

139.	Which one of these is most reactive ?A. NaB. KC. PbD. Mg.
Answer» Correct Answer - B K is more reactive than Na. Pb and Mg are less reactive than Na.

Discussion

140.	Hot sodium hydroxide when treated with chlorine givesA. Sodium chloride and waterB. Sodium chlorate and waterC. Sodium chloride, sodium chlorate and waterD. None of the above.
Answer» Correct Answer - C `6NaOH+3Cl_(2)rarr5NaCl + NaClO_(3)+3H_(2)O`

Discussion

141.	Assertion (A) `Na+KCloverset(900^(@)C)rarrNaCl +K` Reasons (A) Na is more reactive than K
Answer» Correct Answer - C Reason. Potassium is volatile at the reaction temperature (Infact K is more reactive than Na).

Discussion

142.	Which of the following sets of atomic numbers belongs to that of alkali metals?A. 1, 12, 30, 4, 62B. 37, 19, 3, 55C. 9, 17, 35, 53D. 12, 20, 56, 88.
Answer» Correct Answer - B Elements with atomic number 3, 11, 19, 37, 55, 87 are alkali metals.

Discussion

143.	The element with atomic number 55 belongs to which block of the periodic tableA. s-blockB. p-blockC. d-blockD. f-block.
Answer» Correct Answer - A See answer to question 7.

Discussion

144.	Assertion (A) `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(1)` is the configuration of an alkali metal. Reason (A) Alkali metal contain one electron in the s-subshell of valence shell.
Answer» Correct Answer - D The given configuration is that of copper (Group II) and not of alkali metal.

Discussion

145.	Which of the following is used as a source of `O_(2)` in space capsules, submarines etc?A. `K_(2)O`B. `Na_(2)O_(2)`C. `Li_(2)O`D. `Na_(2)O`.
Answer» Correct Answer - B `Na_(2)O_(2)` is used as a source of `O_(2)` in space capsules and submarines `2Na_(2)O_(2)+2CO_(2)rarr2Na_(2)CO_(3)+O_(2)`

Discussion

146.	The outermost electron is most loosely held inA. LiB. NaC. KD. Rb.
Answer» Correct Answer - D Size of Rb is more and therefore it has low I.E.

Discussion

147.	The chloride of one of the following form a hydrateA. LiB. NaC. CsD. Rb.
Answer» Correct Answer - A LiCl is deliquescent and form hydrate of the formula LiCl. `2H_(2)O`

Discussion

148.	The pair of compounds which cannot exist together in aqueous solution areA. `NaH_(2)PO_(4)` and `Na_(2)HPO_(4)`B. `Na_(2)O_(3)` and `NaHCO_(3)`C. NaOH and `NaH_(2)PO_(4)`D. `NaHCO_(3)` and NaOH.
Answer» Correct Answer - C::D A base (NaOH) and an acid salt `(NaH_(2)SO_(4) " or "NaH_(2)PO_(4))` cannot exist together in a solution.

Discussion

149.	The pair of compounds which cannot exist together in aqueous solution isA. `Na_(2)CO_(3)` and `NaHCO_(3)`B. `NaHCO_(3)` and NaOHC. NaOH and `NaH_(2)PO_(4)`D. Both (B) and (C ).
Answer» Correct Answer - D The pairs would involve acid base reaction to form salt and water. `NaHCO_(3)+NaOH rarrNa_(2)CO_(3)+H_(2)O` `2NaOH + NaH_(2)PO_(4)rarrNa_(3)PO_(4)+2H_(2)O`

Discussion

150.	The pair of compounds which cannot exist together isA. `NaHCO_(3)` and NaOHB. `Na_(2)CO_(3)` and `NaHCO_(3)`C. `Na_(2)CO_(3)` and NaOHD. `NaHCO_(3)` and NaCl.
Answer» Correct Answer - A An acid salt `(NaHCO_(3))` cannot exist with a base (NaOH) in a solution.

Discussion

Explore topic-wise InterviewSolutions in .

Which of the following is monovalent ?A. Alkali metalsB. Alkaline earth metalsC. MetalloidsD. Metals.

Lithium shows diagonal relationship withA. MagnesiumB. BerylliumC. AluminiumD. Boron.

How does the ionisation energy of 1st group elements very ?A. increases down the groupB. decreases down the groupC. remain unchangedD. variation is not regular.

Which of the following is not a white crystalline solid ?A. `LiHCO_(3)`B. `NaHCO_(3)`C. `KHCO_(3)`D. `CsHCO_(3)`.

Which of the following statement is not true to explain that first member in a group differs in many respects from other members of its group ?A. Small sizeB. High electronegativityC. Nonavailability of d-orbitals for bondingD. Similar ionic charges.

Microcosmic salt isA. `Na(NH_(4))HPO_(4).4H_(2)O`B. `Na(NH_(4)).H_(2)O`C. `Na(NH_(3))HPO_(4). 4H_(2)O`D. `K(NH_(4))HPO_(3).2H_(2)O`

Most insoluble salt of Li in water isA. `Li_(2)CO_(3)`B. `Li_(2)SO_(4)`C. `Li_(3)PO_(4)`D. LiF.

Sodium ordinarily does not show an oxidation state of `+2`, because of itsA. high first ionization energyB. high second ionization energyC. large ionic radiusD. high electronegativity.

The most insoluble salt of sodium isA. `Na_(4)[Fe(CN)_(6)]`B. `Na_(3)[Fe(CN)_(6)]`C. `Na[Sb(OH)_(6)]`D. `Na[Fe(CN_(5))NO].2H_(2)O`.

A colloidal solution of Na in ether isA. golden yellow in colourB. blue in colourC. colourlessD. violet in colour.

Which of the following has lowest thermal stability ?A. `Li_(2)CO_(3)`B. `Na_(2)CO_(3)`C. `K_(2)CO_(3)`D. `Rb_(2)CO_(3)`.

The alkali metalsA. forms salt like hydridesB. form salts which are predominantly covalentC. show decreased chemical reactivity with dry oxygen in going from Li to CsD. show increasing electronegativity from Li to Cs.

Caesium forms chiefly ionic compounds becauseA. the valence electrons are poorly bound to the nucleusB. its electronegativity is very highC. its ionization energy is very lowD. the polarizablitiy of the cation is high.

Caesium oxide will beA. AcidicB. BasicC. Weakly basicD. Amphoteric.

Caesium oxide will beA. very strongly basicB. acidicC. Weakly basicD. Amphoteric.

Sodium when dropped in water catches fire becauseA. it has higher atomic massB. it is a metalC. it is highly electropositive is natureD. the hydrogen gas evolved in the reaction is combustible in nature.

Which one of the following alkali metals emit light of longest wavelength in the flame test ?A. NaB. LiC. KD. Cs.

`Li_(2)O_(2)` is formed whenA. Li is heated strongly in excess of airB. LiOH is heated in an atmosphere of `O_(2)`C. `H_(2)O_(2)` and alcohol are added to a solution of LiOH in waterD. None of these.

Which of the following properties is not true for an alkali metal ?A. Low atomic volumeB. Low ionization energyC. Low densityD. Low electronegativity.

Sodium nitrate decomposes above `800^(@)C` to giveA. `N_(2)`B. `O_(2)`C. `NO_(2)`D. `Na_(2)O`.

Which of the following decomposes on heating ?A. LiOHB. NaOHC. KOHD. CsOH.

Which of the following is correct ?A. In the Castner process of sodium extraction, NaCl is used as an electrolyteB. Sodium reduces `CO_(2)` to carbonC. Magnesium reacts with cold water and liberates hydrogenD. Magnallium is one alloy of Mg and zinc.

Chill salt petre isA. `NaNO_(3)`B. `Na_(2)SO_(4)`C. `KNO_(3)`D. `OH^(-)`

Which out of the following compounds is the most stable ?A. LiClB. LiFC. LiBrD. LiI.

The fusion mixture is a mixture ofA. `K_(2)CO_(3)+Na_(2)CO_(3)`B. `KHSO_(4)+NaHSO_(4)`C. `K_(2)CO_(3)+NaHSO_(4)`D. `KHSO_(4)+Na_(2)SO_(3)`

Excess of `Na^(+)` ions in our system causesA. DiabetesB. AnaemiaC. Low blood pressureD. High blood pressure.

`LiAlH_(4)` is obtained by reacting an excess of…. With an ethereal solution of `AlCl_(3)`A. LiClB. LiHC. LiD. LiOH.

The correct sequence of the alkali metals in the group isA. Fr, Na, K, Rb, Cs, LiB. Li, Na, K, Rb, Cs, FrC. Na, K, Rb, Cs, Fr, LiD. Rb, Cs, Li, Na, K.

Alkali metals have very small value of electronegativity. The electronegativity down the groupA. increasesB. decreasesC. remains sameD. none of these.

Assertion (A) `underset(CH)overset(C)("|||")+2Lioverset(NH_(3)(i))rarrunderset(CLi)overset(CLi)("|||")+H_(2)` Reasons (A) Alkali metals form acetylides with terminal alkynes.

Which of the following alkali metal halides has the lowest lattice energy ?A. LiFB. NaClC. KBrD. CsI.

Alkali metals in each period haveA. Smallest sizeB. Lowest ionization energyC. Highest electron affinityD. Highest electronegativity.

Which among the following is most soluble in alcohol ?A. `CsClO_(4)`B. `LiClO_(4)`C. `KClO_(4)`D. `NaClO_(4)`.

The largest ionic radii in water is ofA. `K^(+)`B. `Cs^(+)`C. `Na^(+)`D. `Li^(+)`.

When `CO_(2)` is bubbled into an aqueous solution of `Na_(2)CO_(3)` the following is formedA. `NaOH`B. `NaHCO_(3)`C. `H_(2)O`D. `OH^(-)`

Which of the following is radioactive ?A. `Na^(23)`B. `K^(39)`C. `K^(40)`D. `Ca^(40)`

Which of the following is a man made element ?A. RaB. FrC. RnD. Lr.

Which one of the these is basic ?A. `CO_(2)`B. `SiO_(2)`C. `Na_(2)O`D. `SO_(2)`

Which one of these is most reactive ?A. NaB. KC. PbD. Mg.

Hot sodium hydroxide when treated with chlorine givesA. Sodium chloride and waterB. Sodium chlorate and waterC. Sodium chloride, sodium chlorate and waterD. None of the above.

Assertion (A) `Na+KCloverset(900^(@)C)rarrNaCl +K` Reasons (A) Na is more reactive than K

Which of the following sets of atomic numbers belongs to that of alkali metals?A. 1, 12, 30, 4, 62B. 37, 19, 3, 55C. 9, 17, 35, 53D. 12, 20, 56, 88.

The element with atomic number 55 belongs to which block of the periodic tableA. s-blockB. p-blockC. d-blockD. f-block.

Assertion (A) `1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(1)` is the configuration of an alkali metal. Reason (A) Alkali metal contain one electron in the s-subshell of valence shell.

Which of the following is used as a source of `O_(2)` in space capsules, submarines etc?A. `K_(2)O`B. `Na_(2)O_(2)`C. `Li_(2)O`D. `Na_(2)O`.

The outermost electron is most loosely held inA. LiB. NaC. KD. Rb.

The chloride of one of the following form a hydrateA. LiB. NaC. CsD. Rb.

The pair of compounds which cannot exist together in aqueous solution areA. `NaH_(2)PO_(4)` and `Na_(2)HPO_(4)`B. `Na_(2)O_(3)` and `NaHCO_(3)`C. NaOH and `NaH_(2)PO_(4)`D. `NaHCO_(3)` and NaOH.

The pair of compounds which cannot exist together in aqueous solution isA. `Na_(2)CO_(3)` and `NaHCO_(3)`B. `NaHCO_(3)` and NaOHC. NaOH and `NaH_(2)PO_(4)`D. Both (B) and (C ).

The pair of compounds which cannot exist together isA. `NaHCO_(3)` and NaOHB. `Na_(2)CO_(3)` and `NaHCO_(3)`C. `Na_(2)CO_(3)` and NaOHD. `NaHCO_(3)` and NaCl.