Uses of Alkali Metals

Q.

Compared with alkaline earth metals, the alkali metals exhibit:

1. lower ionization energies

2. smaller ionic radii

3. greater hardness

4. high boiling point

Q. Choose the correct statement(s):

1. The oxides and the peroxides of alkali metals are colorless when pure.
2. The superoxides of alkali metals are yellow or orange in color.
3. Oxides are hydrolyzed by water to form the hydroxides.
4. The superoxides of alkali metals are diamagnetic.

Q. When there is excessive oxygen why sodium forms peroxide and others forms superoxide in alkali metals why?

Q.

Match List-I and List-II:

List-I	List-II
(a) Be	(i) treatment of cancer
(b) Mg	(ii) extraction of metals
(c) Ca	(iii) incendiary bombs and signals
(d) Ra	(iv) windows of X-ray tubes
–	(v) bearings for motor engines

Choose the most appropriate answer from the option given below:

1. (a)-(iii), (b)-(iv), (c)-(ii), (d)-(v)

2. (a)-(iv), (b)-(iii), (c)-(i), (d)-(ii)

3. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i)

4. (a)-(iii), (b)-(iv), (c)-(v), (d)-(ii)

Q.

Which among the following statements is incorrect for magnesium metal?

1. It burns in oxygen with a dazzling white flame

2. It reacts with cold water to form magnesium oxide and evolves hydrogen gas

3. It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas

4. It reacts with steam to form magnesium hydroxide and evolves hydrogen gas

Q. Nitrogen can be obtained :

1. By making ammonium nitrite and ​then warming it.​
2. By the thermal ​decomposition ​of barium azide.
3. From liquified air by fractional distillation​.
4. All of the above

Q. Which of the following alkali metals have the least ionization enthalpy?

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

Q. Assertion :Sodium carbonate extract of a salt containing sulphide ions gives a violet colour with appropriate reagent. Reason: The reagent sodium nitroprusside gives violet colour due to the formation of sodium thionitroprusside.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q.

Is Silicate A Salt?

Q.

Molecular formula of Glauber’s salt is

1. $MgS{O}_4.7H_{2}O$

2. $CuS{O}_4.5H_{2}O$

3. $FeS{O}_4.7H_{2}O$

4. $N{a}_{2}S{O}_4.10H_{2}O$

Q.

The molecular formula of epsom salt is

1. $MgS{O}_4.6H_{2}O$

2. $FeS{O}_4.7H_{2}O$

3. $MgS{O}_4.7H_{2}O$

4. None of these

Q. Ethers in contact with air for a long time form peroxides. The presence of peroxide can be tested by adding $F{e}^{2+}$ ions followed by the addition of:

1. $KCNS$
2. $SnC{l}_2$
3. $HgC{l}_2$
4. $KI$

Q. Sodium is found more useful than potassium. If true enter 1, if false enter 0.

Q.

Q. Which of the following statements is incorrect for hydrogen peroxide?

1. It is stored in plastic bottles in dark
2. It acts as an oxidising as well as a reducing agent
3. It is used as a bleaching agent
4. It has acidic as well as basic properties

Q. Which of the following reagent is used as fixer in photography?

1. $N{a}_2{S}_2{O}_3\cdot 5H_{2}O$
2. $AgBr$
3. Both A and C
4. $AgN{O}_3$

Q. What is the reason why chlorine gas turns colourless potassium bromide solution to coloured?

Q. $Fe{Cl}_3$ gives blood red colour with ${NH}_{4}SCN$. If $H_{2}S$ gas is passed and filtered then filtrate does not give red colour with ${NH}_{4}SCN$.

1. ${NH}_{4}Cl$
2. ${\left[Fe\right(SCN\left)\right]}^{2+}$
3. $noneofthese$
4. $Fe{Cl}_2$

Q. When fluorine reacts with hot and conc. NaOH then products obtained are:

1. $NaF+H_{2}O+O_2$
2. $NaF+H_{2}O+O{F}_2$
3. $NaF+HF+O_2$
4. $HF+NaF+H_{2}O$

Q. Acidity of acid produced when conc. nitric acid reacts with calcium phosphate is :

Q. Assertion :High concentration Sulphide gives positive test with sodium nitroprusside. Reason: Acidified $H_{2}S$ gives negative test with sodium nitroprusside.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. Both Assertion and Reason are incorrect

Q. Select the metals (in List I) with the specific properties of the compounds (in List II).

Q. The gas turns $KI$ paper brown. It gives reddish brown fumes. Guess the anion.

1. $N{O}_3^{-}$
2. $C{l}^{-}$
3. $S{O}_3^{2-}$
4. $C{O}_3^{2-}$

Q. Molecular formula of Glauber's salt is:

1. $MgS{O}_4.7H_{2}O$
2. $N{a}_{2}C{O}_3.10H_{2}O$
3. $N{a}_{2}S{O}_4.10H_{2}O$
4. $FeS{O}_4.7H_{2}O$

Q. In sodium carbonate bead test, chromium salts (green) change coloured bead to :

1. yellow, $PbCr{O}_4$
2. yellow, $BaCr{O}_4$
3. yellow, ${Na}_{2}Cr{O}_4$
4. orange, ${Na}_2{Cr}_2{O}_7$

Q. "$K{O}_2$ is $O_2$ absorber and $C{O}_2$ producer." It is also used in submarines."
Answer whether the above statement is true or false.
If true enter 1, else enter 0.

Q. What are the products formed when moist chlorine gas is reacted with hypo?

1. $N{a}_{2}S{O}_4,S,HCl$
2. $N{a}_{2}S{O}_3,S,HCl$
3. $N{a}_2{S}_4{O}_6,NaCl,HCl$
4. $N{a}_2{S}_4{O}_6,N{a}_{2}S{O}_3,HCl$

Q. In an alkaline solution, sodium nitroprusside gives a violet colour with:

1. $S^{2-}$
2. $S{O}_3^{2-}$
3. $S{O}_4^{2-}$
4. $N{O}_2^{-}$

Q. $N{a}_2{B}_4{O}_7.10H_{2}O\stackrel{Heat}{\to }X+NaB{O}_2+H_{2}O$

1. $N{a}_{3}B{O}_3$ and Cr($B{O}_2$)${}_3$
2. $B_2{O}_3$ and $CrB{O}_3$
3. $B_2{O}_3$ and Cr($B{O}_2$)${}_3$
4. $N{a}_{2}B{O}_4{O}_7$ and Cr($B{O}_2$)${}_3$

Q. Match List-I with List-II :

List-I	List-II
Elements	Properties
(a) Li	(i) Poor water solubility of $I^{-}$
(b) Na	(ii) Most abundant element in cell fluid
(c) K	(iii) Bicarbonate salt used in fire extinguisher
(d) Cs	(iv) Carbonate salt decomoses easily on heating

Choose the correct answer from the options given below :

JEE MAIN 2021

1. (a) - (i), (b) - (iii), (c) - (ii), (d) - (iv)
2. (a) - (iv), (b) - (iii), (c) - (ii), (d) - (i)
3. (a) - (iv), (b) - (ii), (c) - (iii), (d) - (i)
4. (a) - (i), (b) - (ii), (c) - (iii), (d) - (iv)