Tag: chemistry

Questions Related to chemistry

When aluminium hydroxide is reacted with excess ammonium hydroxide, the insoluble compound is formed. Mark the correct formula.

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $\displaystyle { \left[ { Al\left( OH \right) } _{ 4 } \right] }^{ 1- }$

  2. $\displaystyle { \left[ { Al\left( OH \right) } _{ 5 } \right] }^{ 2- }$

  3. $\displaystyle { \left[ { Al\left( OH \right) } _{ 6 } \right] }^{ 3- }$

  4. $\displaystyle { \left[ { Al\left( OH \right) } _{ 7 } \right] }^{ 4- }$

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Correct Option: C

If the pH of an alkali metal hydroxide is 13.6, the concentration of hydroxide is ;

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. More than 1 M

  2. Between 0.1 M and 1 M

  3. Between 0.01 M and 1 M

  4. Less than 0.001 M

Show answer
Correct Option: B
Explanation:
Given that :

$pH = 13.6$

Thus, $pOH = 14 - 13.6$

                     $=0.4$
Hence,
$[O{H^ - }] = lo{g^{ - 1}}( - 0.4)$

               $ = 0.3979$

Therefore the value of $[O{H^ - }]$ is between $0.1M$ and $1M$.

Therefore, the option is B.

A salt contains two atoms of iron, three atoms of sulphur and twelve atoms of oxygen. Identify the corresponding acid and base from which it is formed.

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $H _2 SO _4, Fe (OH) _2$

  2. $H _2 SO _3, Fe (OH) _2$

  3. $H _2 SO _3, Fe (OH) _3$

  4. $H _2 SO _4, Fe (OH) _3$

Show answer
Correct Option: D
Explanation:

$Fe _{2}(SO _{4}) _{3}$ is the salt formed from $Fe(OH) _{3}$ and $H _{2}SO _{4}$. The balanced chemical equation can be written as:
$2Fe(OH) _{3} + 3H _{2}SO _{4} \rightarrow Fe _{2}(SO _{4}) _{3} +6H _{2}O$

Colourless solution of silver nitrate is taken in two test tubes A and B. Metal plates of copper and platinum are dipped into test tubes, A and B respectively. Content of test tubes ____________.

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. B turns green

  2. B turns blue

  3. A turns blue

  4. A remains colourless

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Correct Option: C
Explanation:

In test tube A, displacement reaction takes place as copper being more reactive displaces silver from silver nitrate solution thus leading to the formation of copper nitrate which is blue in colour. The chemical reaction can be written as:
$Cu + Ag(NO _{3}) _{2} \rightarrow Cu(NO _{3}) _{2} + Ag$

When sodium iodide is heated with concentrate sulphuric acid,the vapour evolved is-

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. Iodine

  2. ${SO} _{2}$

  3. Sulphuric acid

  4. Oxygen

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Correct Option: A
Explanation:

$2NaI+{ H } _{ 2 }{ SO } _{ 4 }\xrightarrow [  ]{ heated } { Na } _{ 2 }{ SO } _{ 4 }+2HI$
$2HI\xrightarrow [  ]{ heated }  {H} _{2}+{I} _{2}$

Which of the following equation is not correct?

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. Amphoteric oxide / Hydroxide + Acid$\rightarrow$ Salt + Water

  2. Amphoteric oxide / Hydroxide + Alkali$\rightarrow$ Salt + Water

  3. Metal + Alkali$\rightarrow$ Salt + Water

  4. Metal + Alkali$\rightarrow$ Salt + Hydrogen

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Correct Option: C

Which of the following equation represents action of alkali on oxide?

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $ZnO+2NaOH\rightarrow Na _2ZnO _2+H _2O$

  2. $Zn\begin{pmatrix}OH\end{pmatrix} _2+2NaOH\rightarrow NaZnO _2+2H _2O$

  3. $PbO+2NaOH\rightarrow Na _2PbO _2+2H _2O$

  4. Both A and C

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Correct Option: A
Explanation:

Oxides of certain metals react with acid and alkali to give salt and water.
$ZnO+2NaOH\rightarrow Na _2ZnO _2+H _2O$ is the only correct equation.

Which of the following equation represents action of alkali on hydroxide?

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $ZnO+2NaOH\rightarrow Na _2ZnO _2+H _2O$

  2. $Zn\begin{pmatrix}OH\end{pmatrix} _2+2NaOH\rightarrow Na _2ZnO _2+2H _2O$

  3. $PbO+2NaOH\rightarrow Na _2PbO _2+2H _2O$

  4. Both A and C

Show answer
Correct Option: B
Explanation:

$Zn\begin{pmatrix}OH\end{pmatrix} _2+2NaOH\rightarrow Na _2ZnO _2+2H _2O$ represents action of alkali on hydroxide.

Complete the following equation
$PbO+NaOH\rightarrow$

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $PbO+2NaOH\rightarrow Na _2PbO _2+H _2O$

  2. $PbO+NaOH\rightarrow2Na _2PbO _2+H _2O$

  3. $PbO+2NaOH\rightarrow2Na _2PbO _2+H _2O$

  4. $PbO+NaOH\rightarrow Na _2PbO _2+H _2O$

Show answer
Correct Option: A
Explanation:

$PbO+2NaOH\rightarrow Na _2PbO _2+H _2O$ 

Which of the following equation represents action of alkali on aluminium hydroxide?

action of alkalis on some metals and metal oxides analytical chemistry properties of acids and bases acids, bases and salts chemistry

  1. $Al\begin{pmatrix}OH\end{pmatrix} _3+NaOH\rightarrow NaAlO _2+2H _2O$

  2. $Al\begin{pmatrix}OH\end{pmatrix} _3+2KOH\rightarrow2KAlO _2+H _2O$

  3. $Al\begin{pmatrix}OH\end{pmatrix} _3+KOH\rightarrow KAlO _2+2H _2O$

  4. Both A and C

Show answer
Correct Option: D