Chemical Reactivity (Group 1)

Q.

What happens when copper is heated in the air?

Q. Which of the following alkali carbonates have high thermal stability?

1. $N{a}_{2}C{O}_3$
2. $L{i}_{2}C{O}_3$
3. $K_{2}C{O}_3$
4. $R{b}_{2}C{O}_3$

Q. Which of the following alkali metals doesn't give ethynide on reacting with ethyne?

1. Na
2. K
3. Li
4. Rb

Q. Which of the following is/are can be distinguished using Iodoform test?

1. Methanol and propan-2-ol
2. Acetaldehyde and methanal
3. Acetone and diethyl ketone
4. All of the above.

Q.

The stability fo peroxide and superoxide of alkali metals increase as we go down to group. Explain giving reason.

Q. The ionic radii of $K^{+},N{a}^{+},A{l}^{3+}\text{and}M{g}^{2+}$ are in the order

1. $N{a}^{+}<K^{+}<M{g}^{2+}<A{l}^{3+}$
2. $A{l}^{3+}<M{g}^{2+}<K^{+}<N{a}^{+}$
3. $A{l}^{3+}<M{g}^{2+}<N{a}^{+}<K^{+}$
4. $K^{+}<A{l}^{3+}<M{g}^{2+}<N{a}^{+}$

Q. Identify Z in the following reaction sequence.
$C{H}_{3}I\underset{Ether}{\overset{Mg}{\to }}X\underset{ii{H}_{2}O}{\overset{i.Dryice}{\to }}Y\underset{RedP}{\overset{C{l}_2}{\to }}Z$

1. $C{H}_{3}COOH$
2. $C{H}_{3}MgI$
3. $C{H}_{3}COCl$
4. $ClC{H}_{2}COOH$

Q.

Why is the highest oxidation state of a metal exhibited in its oxide or fluoride only?

Q. The reaction of $K_3\left[Fe\right(CN{)}_6]$ with freshly prepared $FeS{O}_4$ solution produces a dark blue precipitate called Turnbull’s blue. Reaction of $K_4\left[Fe\right(CN{)}_6]$ with the $FeS{O}_4$ solution in complete absence of air produces a white precipitate X, which turns blue in air. Mixing the $FeS{O}_4$ solution with $NaN{O}_3,$ followed by a slow addition of concentrated $H_{2}S{O}_4$ through the side of the test tube produces a brown ring.

Precipitate X is:

1. $F{e}_4\left[Fe\right(CN{)}_6{]}_3$
2. $Fe\left[Fe\right(CN{)}_6]$
3. $K_{2}Fe\left[Fe\right(CN{)}_6]$
4. $KFe\left[Fe\right(CN{)}_6]$

Q. The correct increasing order of the oxidation states of nitrogen in $NO,N_{2}O,N{O}_2\text{and}{N}_2{O}_3$ is:

1. $N{O}_2<NO<N_2{O}_3<N_{2}O$

2. $N_{2}O<NO<N_2{O}_3<N{O}_2$

3. $N{O}_2<N_2{O}_3<NO<N_{2}O$

4. $N_{2}O<N_2{O}_3<NO<N{O}_2$

Q.

Predict the formula of the stable binary compounds that would be formed by the combination of the following pairs of elements.
(a) Lithium and oxygen
(b) Magnesium and nitrogen
(c) Aluminium and iodine
(d) Silicon and oxygen
(e) Phosphorus and fluorine
(f) Element 71 and fluorine

Q. Select the incorrect statement.

1. Sodium peroxide dissolves in cold water giving $H_2{O}_2$ and $NaOH$
2. Both $LiN{O}_3$ and $NaN{O}_3$ on heating separately decompose and each liberates two gases $N{O}_2$ and $O_2$
3. Alkali metals are prepared only by the electrolysis of their fused chlorides
4. Sodium react vigorously with water than Lithium

Q.

Why is iodine less reactive than bromine?

Q. Which reagent can differentiate between benzaldehyde and acetophenone?

1. $\left[Ag\right(N{H}_3{)}_2{]}^{+}$
2. $I_2/NaOH$
3. Fehling's solution
4. (a) and (b) above.

Q. A salt is added to the neutral ferric chloride solution to give deep red colour which on heating decomposes to a brown-red precipitate. Which of the following will be present in the salt?

1. Nitrite ion
2. Carbonate ion
3. Acetate ion
4. Sulphate ion

Q. Nitrogen dioxide cannot be obtained by heating:

1. $KN{O}_3$
   
2. $LiN{O}_3$
3. $RbN{O}_3$
   
4. $NaN{O}_3$

Q.

The S- block elements are fcharacterissed by their larger atomic sizes lower ionisation enthalpies invariable +1 oxidation state and solubilities of their oxosalts. In the light of these features describe the nature of their oxides, halides and oxosalts.

Q. Identify the end product (C) in the following sequence.
$C_2{H}_{5}OH\underset{\text{Pyridine}}{\overset{SOC{l}_2}{\to }}A\stackrel{\text{(alc.)}KCN}{\to }B\underset{\text{Heat}}{\overset{2H_{2}O/H^{+}}{\to }}C$
[1 Mark]

1. $C_2{H}_{5}Cl$
2. $C_2{H}_{5}CN$
3. $C_2{H}_{5}COOH$
4. $C_2{H}_{5}CON{H}_2$

Q. The following compounds have been arranged in order of their increasing thermal stabilities. Identify the correct order.
$K_{2}C{O}_3\left(I\right),MgC{O}_3\left(II\right),CaC{O}_3\left(III\right),BeC{O}_3\left(IV\right)$

1. I < II < III < IV
2. IV< II < III < I
3. IV< II < I < III
4. II < IV < III < I

Q. Which one of the following alkali metal is highly reactive ?

1. Li
2. Cs
3. K
4. Na

Q.

Balance the equation $\mathrm{Al}+\mathrm{FeO}\to {\mathrm{Al}}_2{\mathrm{O}}_3+\mathrm{Fe}$

Q. Lithium react directly with nitrogen of air to form :

1. Lithium nitrite
2. Lithium nitrate
3. Lithium oxide
4. Lithium nitride

Q. Which one of the following is most covalent in nature among lithium halide?

1. LiF
2. LiCl
3. LiI
4. LiBr

Q. The metallic lustre exhibited by sodium is explained by:

1. Diffusion of sodium ions
2. Oscillation of loose electrons
3. Excitation of free protons
4. Existence of body centered cubic lattice

Q.

Explain the increase in chemical reactivity of metals as we go down the group.

Q.

How to write the formula for Calcium nitride?

Q. Choose the correct statement among the following ?

1. Alkali metals can react with halogens
2. All of the above
3. Alkali metals react with $H_2$ to form hydrides
4. Alkali metal hydrides are ionic solid

Q.

What are the group one elements called?

Q. Which gas will be released when lithium nitride is treated with water ?

1. $H_2$
2. $N_2$
3. $O_2$
4. $N{H}_3$

Q. The aqueous solution of an unknown sodium salt gives the following reactions:
(I) It gives white turbidity with dilute $HCl$ solution.
(II) It decolourises a solution of iodine in potassium iodide.
(III) It gives a white precipitate with $AgN{O}_3$ solution which changes colours and finally becomes black on standing.
The unknown sodium salt is:

1. Sodium sulphite
2. Sodium sulphide
3. Sodium bisulphite
4. Sodium thiosulphate