Tag: chemistry

Questions Related to chemistry

A metal 'M' has shining appearance and reacts with hot water and also with dilute hydrochloric acid to evolve hydrogen gas. The metal 'M' is:

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. can be copper because it lies above hydrogen in the reactivity series, i.e., more reactive than hydrogen

  2. can be gold because it lies below hydrogen in the reactivity series, i.e., more reactive than hydrogen

  3. cannot be gold because it lies above hydrogen in the reactivity series, i.e., less reactivity than hydrogen

  4. cannot be copper because it lies below hydrogen in the reactivity series, i.e., less reactive than hydrogen

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Correct Option: D

The reactivity series is a list of metals arranged in the order of their _______ activities.

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. decreasing

  2. Increasing

  3. chemical

  4. physical

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Correct Option: A
Explanation:

The reactivity series is a series of metals, arranged in order of reactivity from highest to lowest. It is used to determine the products of single displacement reactions, whereby metal A will replace another metal B in a solution if A is higher in the series.

Sodium reacts with zinc chloride to form -

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. Sodium chloride

  2. Zinc metal

  3. Both (a) and (b)

  4. None

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Correct Option: C
Explanation:

$2Na + ZnCl _2 \rightarrow 2NaCl + Zn$

Here, more reactive metal sodium is displacing less reactive metal zinc from its compound.

The metallic oxide/s which cannot be reduced by normal reducing agents.

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. Magnesium oxide

  2. Copper $(II)$ oxide

  3. Zinc oxide

  4. Iron $(III)$ oxide

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Correct Option: A
Explanation:

Among given metal oxides, magnesium have very low reduction potential so it can not be reduced by normal reducing agents.

Which is the least reactive metal in the reactive series?

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. Copper

  2. Mercury

  3. Silver

  4. Gold

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Correct Option: D
Explanation:

Gold is least reactive metal because of higher standard reduction potential value.

Name a metal from the activity series which displaces hydrogen from steam?

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. Zinc

  2. Iron

  3. Copper

  4. Magnesium

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Correct Option: D
Explanation:

Magnesium can displace hydrogen from steam. Mg is better reducing agent than hydrogen as Mg les above hydrogen in the reactivity series.
Hence, the tendency for the reaction $\displaystyle Mg \rightarrow Mg^{2+} + 2e^-$ is greater than the tendency for the reaction $\displaystyle 2H^+ + 2e^- \rightarrow H _2$. Hence, Mg will be oxidised and $\displaystyle H^+$ will be reduced.

Metals above hydrogen in activity series :

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. react with base to liberate hydrogen ions

  2. react with acids to liberate hydrogen gas

  3. react with water at ordinary temperature

  4. none of the above

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Correct Option: B
Explanation:

The activity series is a listing of the metals in decreasing order of their reactivity with hydrogen ion sources such as water and acids. In the reaction with hydrogen ion source the metal is oxidized to a metal ion and the hydrogen is reduced to hydrogen gas. They are also good reducing agents and poor oxidizing agents.

A small piece of silver is placed in a solution containing both magnesium nitrate and copper (II) nitrate. Which one of the following occurs?

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. No reaction takes place

  2. The silver dissolves and only copper is precipitated

  3. The silver dissolved and only magnesium is precipitated

  4. A mixture of magnesium and copper forms on the silver

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Correct Option: A
Explanation:

Silver is the metal which is present at the bottom of reactivity series below $Mg$ and $Cu$ metals so it cannot displace these metals from its solution. In this case, no reaction takes place by this piece of silver.

In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of:

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. $Cl _2$

  2. $H _2$

  3. $N _2$

  4. $O _2$

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Correct Option: C
Explanation:

In order to prevent the spoilage of potato chips, they are packed in plastic bags in an atmosphere of $N _2$ to prevent from being rancid or oxidised. 
Nitrogen is added to the potato chip packet to add strength to the packaging. Normally aluminium cans are used for packaging beverages, these beverages are carbonated drinks and the carbon dioxide present in them provides the internal pressure in the can and thus gives internal strength to the aluminium can. But in non-carbonated drinks, there is no carbon dioxide present and so Nitrogen is added to it to give the required strength to the packing.

Which of the following metal will not displace hydrogen gas from dilute $H _2SO _4$?

chemistry reactivity series and electrochemistry reactivity series and displacement reactions chemical properties of metals chemical properties of metals and non metals

  1. Zinc

  2. Iron

  3. Copper

  4. Aluminium

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Correct Option: C
Explanation:

Since, the copper is present below the hydrogen in the activity series it cannot displace hydrogen from the sulphuric acid.