Acidic Character, Basic Character and Nature of Oxides

Q.

Which of the following oxides is not expected to react with sodium hydroxide? [CBSE AIPMT 2009]

1. $Si{O}_2$

2. $B_2{O}_3$

3. $CaO$

4. $BaO$

Q. For $M^{2+}/M$ and $M^{3+}/M^{2+}$ systems the $E^o$ values for some metals are as follows:

$\begin{array}{cccc}C{r}^{2+}/Cr& -0.9V& C{r}^{3+}/C{r}^{2+}& -0.4V\\ M{n}^{2+}/Mn& -1.2V& M{n}^{3+}/M{n}^{2+}& +1.5V\\ F{e}^{2+}/Fe& -0.4V& F{e}^{3+}/F{e}^{2+}& +0.8V\end{array}$

Use this data to comment upon:

A. the stability of $F{e}^{3+}$ in acid solution as compared to that of $C{r}^{3+}$ or $M{n}^{3+}$

B. the ease with which iron can be oxidized as compared to a similar process for either chromium or manganese metal.

Q. Which of the following is the most basic oxide?

1. $N_{2}O$
2. $MgO$
3. $N{a}_{2}O$
4. $FeO$

Q. The most acidic oxide among the following is:

1. $MgO$
2. $S{O}_3$
3. $C{l}_2{O}_7$
4. $N{O}_2$

Q. What will happen during the electrolysis of aqueous solution of $CuS{O}_4$ by using platinum electrodes?

1. Copper will deposit at cathode
2. Oxygen will be released at anode
3. Copper will deposit at anode
4. Copper will dissolve at anode

Q.

p - block elements form acidic, basic and amphoteric oxides. Explain each property by giving two examples and also write the reactions of these oxides with water.

Q. Is it true that under certain conditions, $Mg$ can reduce $A{l}_2{O}_3$and $Al$ can reduce $MgO$? What are those conditions?

Q. Which of the following is the most acidic in nature?

1. $Si{O}_2$
2. $P_4{O}_{10}$
3. $C{O}_2$
4. $S{O}_3$

Q. How would you account for the increasing oxidising power in the series $V{O}_2^{+}<C{r}_2{O}_7^{2-}<Mn{O}_4^{-}$?

Q. What will happen during electrolysis of aqueous solution of $CuS{O}_4$ in the presence of $Cu$ electrodes?

1. Oxygen will be released at anode
2. Copper will deposit at anode
3. Copper will deposit at cathode
4. Copper will dissolve at anode

Q.

Electrolytic reduction process is used for the extraction of

1. highly electronegative metals.

2. highly electropositive metals.

3. transition metals.

4. noble metals.

Q.

Which one of the following reactions is not possible?

1. $\mathrm{Ca}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{CaSO}}_4+{\mathrm{H}}_2$

2. $\mathrm{Cu}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{CuSO}}_4+{\mathrm{H}}_2$

3. $\mathrm{Zn}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{ZnSO}}_4+{\mathrm{H}}_2$

4. $\mathrm{Mg}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{MgSO}}_4+{\mathrm{H}}_2$

Q.

Give reasons why:

Metals are reducing agents and non-metals are oxidizing agents.

Q.

Explain how the following metals are obtained from their compounds by the reduction process.

(a) Metal X which is low in reactivity series

(b) Metal Y which is in the middle of the reactivity series

(c) Metal Z which is high up in the reactivity series.

Q. For the given cell, $Mg|M{g}^{2+}||C{u}^{2+}|Cu$

1. $Cu$ is an oxidising agent
2. $Cu$ is cathode
3. $Mg$ is cathode.
4. The cell reaction is $Mg+C{u}^{2+}\to M{g}^{2+}+Cu$

Q. For 2SO2 + O2→ 2SO3 rate of disappearanceof SO2 is 4 x 10 power minus 3 M-s-1 , at t=10 sec. Then, the amount of SO3 formed & amount of O2 consumed at t 10 sec respectively are

Q. The correct statements among (a) to (d) are :
(a) saline hydrides produce $H_2$ gas when reacted with $H_{2}O$.
(b) reaction of $LiAl{H}_4$ with $B{F}_3$ leads to $B_2{H}_6$.
(c) $P{H}_3$ and $C{H}_4$ are electron-rich and electron-precise hydrides, respectively.
(d) $HF$ and $C{H}_4$ are called as molecular hydride

1. (a), (b), (c) and (d)
2. (a), (c) and (d) only
3. (c) and (d) only
4. (a), (b) and (c) only

Q.

A student puts one big iron nail each in four test tubes containing solutions of zinc sulphate, aluminium sulphate, copper sulphate and iron sulphate. A reddish-brown coating was observed only on the surface of iron nail which was put in the solution of

1. zinc sulphate

2. iron sulphate

3. copper sulphate

4. aluminium sulphate

Q. The decrease in stability of higher oxidation state in p - block with increasing atomic number is due to

1. Increase in bond energy as going down the group
2. The reluctance of s - sub shell electrons to participate in the chemical bonding
3. Both are correct
4. None is correct.

Q.

Is Lithium an alkali metal?

Q.

In which of the following option the order of arrangement does not agree with the variation of property indicated against it

a) Li<Na<K<Rb(increasing metallic radius)

b) B<C<N<O(increasing 1st ionisation enthalpy)

c)I<Br<Cl<F(increasing electron gain enthalpy)

d) Al³⁺<Mg²⁺<Na⁺<F^-(increasing ionic size)

Q.

Select the correct answer from the list in the bracket:

The cation discharged at the cathode most readily, $\left({\mathrm{Fe}}^{2+},{\mathrm{Cu}}^{2+},{\mathrm{Pb}}^{2+},{\mathrm{H}}^{+}\right)$

Q. Assertion: $Mg$ cannot be obtained by reduction of its metal oxide by aluminium.

Reason: $Mg$ is less electropositive than $Al$

1. If both assertion and reason are true and reason is the correct explanation of assertion.
2. If both assertion and reason are false.
3. If both assertion and reason are true but reason is not the correct explanation of assertion.
4. If assertion is true but reason is false.

Q.

Which of the following elements produces basic oxide on reacting with oxygen?

1. Chlorine

2. Sulphur

3. Phosphorus

4. Magnesium

Q. Give reasons why hydrogen resembles alkali metals?

Q.

Three test tubes $\mathrm{A}$, $\mathrm{B}$ and $\mathrm{C}$ are taken with ${\mathrm{CuSO}}_4$, ${\mathrm{FeSO}}_4$ and ${\mathrm{AgNO}}_3$ solutions respectively. What are the observations if:

a. $\mathrm{Fe}$metal is added to ${\mathrm{CuSO}}_4$ solution in the test tube $\mathrm{A}$?

b. $\mathrm{Cu}$ turnings are added to ${\mathrm{FeSO}}_4$ solution in the test tube $\mathrm{B}$?

c. $\mathrm{Zn}$ is added to ${\mathrm{AgNO}}_3$ solution in the test tube $\mathrm{C}$?

Q. Although thermodynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of aluminium. Why?

Q. Most basic oxide out of following is:

1. $N{a}_{2}O$
2. $CaO$
3. $MgO$
4. $FeO$

Q. Consider the oxy acid $HCl{O}_n$ series, here value of $n$ is 1 to 4, then incorrect statement regarding these oxy acids is:

1. Acidic character of oxy acids increase with in increasing value of $n$
2. Oxidising power of oxy acids increases with decreasing value of $n$
3. Thermal stability of oxy acids decreases with increasing value of $n$
4. $Cl-O$ bond order decreases with decreasing value of $n$

Q. The correct order of metal-carbon bond strength in the given metal carbonyls is:

1. $\left[Fe\right(CO{)}_4{]}^{2-}>\left[Co\right(CO{)}_4{]}^{-}>\left[Ni\right(CO{)}_4]$
2. $\left[Ni\right(CO{)}_4]>[Co(CO{)}_4{]}^{-}>[Fe(CO{)}_4{]}^{2-}$
3. $\left[Fe\right(CO{)}_4{]}^{2-}>\left[Ni\right(CO{)}_4]>[Co(CO{)}_4{]}^{-}$
4. $\left[Ni\right(CO{)}_4]=[Co(CO{)}_4{]}^{-}=[Fe(CO{)}_4{]}^{2-}$