Tag: patterns and properties of metals

Questions Related to patterns and properties of metals

The electrochemical cell shown below is a concentration cell.
$M|{ M }^{ 2+ }$ (saturated solution of a sparingly soluble salt, $M{X} _{2})\parallel {M}^{2+}(0.001 mol{dm}^{-3})| M$. 
The emf of the cell depends on the difference in concentrations of ${M}^{2+}$ ions at the two electrodes.
The emf of the cell at $298K$ is $0.099V$
The solubility product (${K} _{sp}:{mol}^{3}{dm}^{-9}$) of ${MX} _{2}$ at $298K$ based on the information available for the given concentration cell is: (take $2.303\times R\times 298/F=0.059V$)

electrical cells patterns and properties of metals chemistry

  1. $1\times {10}^{-15}$

  2. $4\times {10}^{-15}$

  3. $1\times {10}^{-12}$

  4. $4\times {10}^{-12}$

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Correct Option: A

X, Y and Z are elements in Period $3$ of the Periodic Table. The results of some experiments carried out with compounds of these elements are shown.


Element Result of adding the oxide of the element to $H _2O(l)$ Result of adding the chloride of the element of $H _2O(l)$ Result of adding the oxide of the element to $HCl(aq)$
X No reaction Hydrolyses Forms chloride salt
Y Forms hydroxide Dissolves Forms chloride salt
Z Forms acid Hydrolyses Hydrolyses


Which statement could be correct?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. X is Al and Y is Mg

  2. X is Si and Y is Na

  3. Y is Al and Z is P

  4. Y is Na and Z is Al

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Correct Option: B

In which of the following order of hydration energy correct?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. $Li^+ > Na^+ > K^+ > Rb^+ > Cs^+$

  2. $Li^+ < Na^+ < K^+ < Rb^+ < Cs^+$

  3. $Li^+ > Na^+ > K^+ > Cs^+ > Rb^+$

  4. $Li^+ < Na^+ < K^+ < Cs^+ < Rb^+$

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Correct Option: A
Explanation:

Hydration decreases with a decrement in charge density of an ion

Metal which is soft and floats on water is _______ .
chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. aluminium

  2. copper

  3. lead

  4. potassium

  5. iron

  6. lithium

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Correct Option: F
Explanation:

Lithium is lightest elemental metal nearly half as dense as water, so it floats on the surface and ultimately disappears, giving off hydrogen gas and forming a colourless solution of lithium hydroxide.


Hence, the correct option is $\text{F}$

Sodium reacts with water more vigorously than lithium because it :

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. has higher atomic weight.

  2. is a metal.

  3. is more electropositive.

  4. more electronegative.

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Correct Option: C
Explanation:

Sodium reacts with water more vigorously than lithium its more electropositive and will give electrons easily.
Hence option C is correct.

Which of the following does not react with water?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. Sodium ions

  2. Sodium atoms

  3. Potassium ions

  4. Both $A$ and $C$

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Correct Option: D
Explanation:

Sodium ions and potassium ions do not react with water.
The main reason is that have already lost that electron and are therefore much more stable. They don't tend to lose another electron, and they certainly don't try to get that lost electron back, so there's no tendency for them to react.

Which of the following element reacts violently when kept under water?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. $Na$

  2. $Fe$

  3. $Cu$

  4. $Au$

  5. $Ne$

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Correct Option: A
Explanation:

Answer (A)

Sodium reacts violently with water to give $H _2$ gas
$2Na+2H _2O\rightarrow2NaOH+H _2$

Metal cation ionic solids dissolve in solution exothermically.This is best explained by which of the following?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. The hydrogen bonding in the water break apart, releasing large amounts of energy that are used to force a breaking of the ionic structure.

  2. The free floating electrons in the metal cations provide a large measure of electricity when the ionic solid is broken down in the water.

  3. The breaking of the ionic structure, which releases bond energy causing the solution to be exothermic.

  4. The attraction of the cations and anions to the dipoles in water, resulting in a release of energy.

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Correct Option: B
Explanation:
Metal cationic  solids dissolve in solution exothermally due the free floating of electrons in the metal cations provide a large measure of electricity when the ionic solid is broken done in the water.

Hence option B is correct.

The reaction between sodium and water can be made less vigorous by:

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. adding a little alcohol

  2. amalgamatic sodium

  3. adding a little acitic acid

  4. lowering the temperature

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Correct Option: B
Explanation:

If we add sodium to water it floats on the water and reacts very vigorously, rushing around and on the surface producing hydrogen gas and sodium hydroxide. Hence to reduce its vigorousness, it is amalgamated with mercury by making sodium as amalgamating sodium. 

Option (B) is correct.

Which of the following alkali metal(s) form complex hydrides?

chemistry patterns and properties of metals periodic trends in chemical properties alkali metals study of specific groups

  1. Li

  2. K

  3. Na

  4. Rb

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Correct Option: A,C
Explanation:

Lithium and sodium form complex hydrides such as lithium aluminium hydride and sodium borohydride.