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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.
| 1251. |
Which property of sodium is being used in street lights ?A. It shows photoelectric effectB. It has low melting pointC. Sodium atom emits photons in the yellow region of visible spectrum, due to electrically stimulated transitionsD. Sodium vapours show golden colour |
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Answer» Correct Answer - C |
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| 1252. |
`KO_(2)` finds use in oxygen cylinders used for space and submarines. The fact(s) related to such use of `KO_(2)` is /are :A. it produces `O_(2)`B. it produces `O_(3)`C. it absorbs `CO_(2)`D. it absorbs both `CO" and "CO_(2)` |
| Answer» Correct Answer - A::C | |
| 1253. |
`KO_(2)` is used in oxygen cylinders in space and submarines because itA. Absorb `OC_(2)` and increase `O_(2)` contentB. Eliminate moistureC. Absorbs `CO_(2)`D. produces `O_(2)` |
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Answer» Correct Answer - A |
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| 1254. |
Statement-1: In fused state, calcium chloride cannot be used to dry alcohol or `NH_(3)`. Statement-2: Anhy. `CaCl_(2)` is not a good desiccant.A. Statement-1 is True, Statement-2 is True. Statement-2 is a correct explanation for Statement-1.B. Statement-1 is True, Statement-2 is True, Statement-2 is NOT a correct explanation for Statement-1.C. Statement-1 is True, Statement-2 is False.D. Statement-1 is False, Statement-2 is True. |
| Answer» Correct Answer - C | |
| 1255. |
Which of the following ions forms a hydroxide which is highly soluble in water?A. `Ni^(2+)`B. `K^(+)`C. `2n^(2+)`D. `Al^(3+)` |
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Answer» Correct Answer - b Alkali metal hydroxides, i.e. KOH is highly soluble in water. |
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| 1256. |
The colours emitted by excited atoms are characteristics of element. The element famous for the red emission of fireworks and warning flares isA. PbB. MgC. SrD. Ba |
| Answer» Correct Answer - C | |
| 1257. |
The second ionization enthalpy of calcium is more than that the first and yet calcium forms `CaCl_(2)` and not CaCl. Why ? |
| Answer» The higher enthalpy of lattice formation of `Ca^(2+)` ions more than compensates the higher second ionization enthalpy of calcium . | |
| 1258. |
The enthalpy of formation of hypothetical CaCl(s) is found to be - 180 kJ `mol^(-1)` and that of `CaCI_(2)` (s) is -800 kJ `mol^(-1)`. Calculate `Delta_(f)H^(@)` for the disproportionation reaction: `2CaCI(s) to CaCI_(2)(s) + Ca(s)` |
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Answer» The available data is : (i) `Ca(s) + 1//2 CI_(2) (g) to CaCI(s)`, `Delta_(f) H^(@) = - 180 kJ mol^(-1)` (ii) `Ca(s) + CI_(2) (g) to CaCI_(2)(s),` `Delta_(f)H^(@) = - 800 kJ mol^(-1)` multiply eqn. (i) by 2 and subract from eqn. (ii) `Ca(s) + CI_(2) to CaCL(s),` `Delta_(f)H^(@) = - 800 kJ mol^(-2)` `2Ca (s) + CI_(2)(g) to 2CaCI(s),` `Delta_(f)H^(@) = - 360 kJ mol^(-1)` `overline("Subtract" : 2CaCI(s) to CaCI_(2) (s) + Ca (s) , Delta_(f)H^(@) = - 420 kJ mol^(-1))` |
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| 1259. |
`Ca + H_(2) O to` |
| Answer» `Ca + 2H_(2)O to Ca(OH)_(2) + H_(2)` | |
| 1260. |
`CaSO_(4).2H_(2)O overset("Heat")(to)` |
| Answer» `CaSO_(4).2H_(2)O overset("Heat")(to) CaSO_(4) 1//2 H_(2)O + 3//2 H_(2)O` | |
| 1261. |
`Mg (NO_(3))_(2) overset("Heat")(to)` |
| Answer» `2Mg(NO_(3))_(2) overset("Heat")(to) 2MgO + 4NO_(2) + O_(2)` | |
| 1262. |
Complete the following : (i) `CaSO_(4). 2H_(2)O overset("heat")(to)` (ii) `MgO + C + CI_(2) overset("heat")(to)` (iii) `Mg(NO_(3))_(2) overset("Heat")(to)` (iv) `Mg + NO overset("Heat")(to)` `CaC_(2) + N_(2) to` (vi) `Mg_(3)N_(2) + H_(2) O to` |
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Answer» (i) `CaSO_(4).2H_(2)O overset("Heat")(to) CaSO_(4). 1//2 H_(2)O + 3//2 H_(2)O` (ii) `MgO + C + CI_(2) overset("Heat")(to) MgCI_(2) + CO` (iii) `2Mg(NO_(3))_(2) overset("Heat")(to) 2MgO + 4NO_(2) + O_(2)` (iv) `5Mg + 2NO overset("Heat")(to) 2MgO + Mg_(3)N_(2)` (v) `CaC_(2) + N_(2) to CaCN_(2) + C` (vi) `Mg_(3)N_(2) + 6H_(2)O to 3Mg (OH)_(2) + 2NH_(3)` |
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| 1263. |
`Mg+NO_(2)` on burning giveA. `N_(2)`B. `NO`C. `N_(2)O`D. `N_(2)O_(6)` |
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Answer» Correct Answer - b `Mg+NO_(2)rarrMgO+NO` |
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| 1264. |
A metal `X` on heating in nitrogen gas gives `Y,Y` on treatment with `H_(2)O` gives a colourless gas which when passed through `CuSO_(4)` solution gives a blue colour. `Y` is:A. `Mg(NO_(3))_(2)`B. `Mg_(3)N_(2)`C. `NH_(3)`D. `MgO` |
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Answer» Correct Answer - b Only `NH_(3)` gas gives deep blue solution with `CuSO_(4).NH_(3)` is obtained by the reaction of nitride of metal with water. `3Mg+N_(2)rarrMg_(3)N_(2)overset(6H_(2)O)rarrunderset("Coloourless")2NH_(3)uparrow+3Mg(OH)_(2)CuSO_(4)+4NH_(3)rarrunderset("Deep blue colour")[Cu(NH_(3))_(4)]SO_(4)` |
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| 1265. |
A metal `X` on heating in nitrogen gas gives `Y,Y` on treatment with `H_(2)O` gives a colourless gas which when passed through `CuSO_(4)` solution gives a blue colour. `Y` is:A. `Mg(NO_(3))_(2)`B. `Mg_(3) N_(2)`C. `NH_(3)`D. `MgO ` |
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Answer» Correct Answer - B `underset(X)(3Mg)x+ N_(2) overset(Delta) to underset(Y) (Mg_(3) N_(2)),` `underset(Y) (Mg_(3)N_(2)) +6H_(2) O to 3Mh (OH)_(2) underset("Colourless")(+2NH_(3)uarr)` `CuSO_(4) +4NH_(3) to underset("Blue complex")([Cu(NH_(3))_(4)]SO_(4))` |
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| 1266. |
Assertion `: BeCl_(2)` fumes in moist air. Reason : `BeCl_(2)` reacts with moisture to form `HCl` gas.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but reason is not the correct explanation of the assertionC. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - a `BeCl_(2)` gets hydrolysed because of smaller `Be^(2+)` ion `(` having higher charge `).` `BeCl_(2) +2H_(2)O rarr Be(OH)_(2)+2HCl`. |
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| 1267. |
`BeCl_(2) + LiAlH_(4)` |
| Answer» `underset({:("Beryllium"),("chloride"):})(2BeCl_(2)) + underset({:("Lithium"),("aluminium"),("hydride"):})(LiAIH_(4)) to 2BeH_(2) + LiCI + AICI_(3)` | |
| 1268. |
In vapour phase and solid phase the hybridisations of `BeCl_(2)` are x and y. The number of hybridd oribitals in x and p and y are q. Then p+q= |
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Answer» Correct Answer - 7 |
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| 1269. |
Metals form basic hydroxides . Which of the following metal hydroxide is the least basic ?A. `Mg(OH)_(2)`B. `Ca(OH)_(2)`C. `Sr(OH)_(2)`D. `Ba(OH)_(2)` |
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Answer» Correct Answer - A As the ionization enthalpy increases from `Mg to Ba` , the M-O bond becomes weaker and weaker down the group and hence basicity increases down the group . Thus , `Mg(OH)_(2)` is least basic . |
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| 1270. |
What is the hybrid state of `BeCl_(2)` in the vapour state ? What will be the change in hybrid state of `BeCl_(2)` in the solid state ? |
| Answer» In the vapour state at high temperature (1200 K) , Be is sp-hybridized and hence `BeCl_(2)` in linear . In the solid state , `BeCl_(2)` is polymeric . In this structure , each Be has two covalent and two coordinate bonds . Therefore , in the solid state . Be has `sp^(3)`-hybridization . | |
| 1271. |
Some of the Group 2 metal halides are covalent and soluble in organic solvents . Among the following metal halides , the one which is soluble in ethanol isA. `BeCl_(2)`B. `MgCl_(2)`C. `CaCl_(2)`D. `SrCl_(2)` |
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Answer» Correct Answer - A Due to small size , high ionization enthalpy of Be , `BeCl_(2)` is covalent and hence most soluble in organic solvents such as ethanol . |
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| 1272. |
The halide of which alkaline earth metal is covalent and soluble in organic solvents ?A. BeB. MgC. CaD. Sr |
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Answer» Correct Answer - A Because of small size , `Be^(2+)` has the highest polarising power and hence `BeCl_(2)` has the highest covalent character and is thus soluble in organic solvents . |
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| 1273. |
The most electropositive amongst the alkaline earth metals is:A. `Be`B. `Mg`C. `Ca`D. `Ba` |
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Answer» Correct Answer - D Eelctropositive character is the measure of ease of formation of cation by losing electron . With increasing atomic size, the ionization energy decreases and, therefore, the ease of formation of cation by losing the electron increases resulting into more electropositive character of the metal. Down the group, metallic character increases due to decreases in ionisation energy and so electropositive character incrases. |
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| 1274. |
The most electropositive amongst the alkaline earth metals is:A. BerylliumB. MagnesiumC. CalciumD. Barium |
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Answer» Correct Answer - D The electropositive character increases down the group. |
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| 1275. |
The most widely distrubuted alkali metals as chloride in nature is/areA. LiB. Na, KC. CsD. K, Rb |
| Answer» Correct Answer - B | |
| 1276. |
Select the ciorrect statement with respect to alkali metals.A. Melting point decrease with increasing atomic number.B. Potassium is lighter than sodium.C. Salts of Li to Cs impart characteristic colour to an oxidising flame (of Bunsen burner).D. All of these |
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Answer» Correct Answer - D |
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