Tag: chemistry

Questions Related to chemistry

Coil present in electrical water heater made up which alloy:

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. Nichrome

  2. Steel

  3. Brass

  4. Aluminium bronze

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Correct Option: A
Explanation:

An alloy of nickel & chromium (Nichrome) is used in electrical water heater because of its high heating property. 


Option A is correct.

Aluminium appears like gold when mixed with :

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. 90 % Cu

  2. 75 % Ni

  3. 80 % Sn

  4. 80 % Co

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Correct Option: A
Explanation:

Aluminium reacts with 90 % Cu and appears like gold. It is known as rolled gold.

Which of the following form an alloy?

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Zn+Pb$

  2. $Fe+Hg$

  3. $Pt+Hg$

  4. $Fe+C$

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Correct Option: D
Explanation:

Iron and Carbon form a significant number of alloys including Steel.


Hence option D is correct.

Which of the following set of metals can form alloy.

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Cu$ and $Au$

  2. $Li$ and $Na$

  3. $Fe$ and $Hg$

  4. All of the above

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Correct Option: A
Explanation:

Metals combined with other substances to make them stronger, harder, lighter, or better in some other way. An alloy like this will form only if the atoms of the base metal and those of the alloying agent are of roughly similar size. In most substitution alloys, the constituent elements are quite near one another in the periodic table. 

Corinthian bronze, is an alloy of copper with gold or silver.
Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, tungsten, and tantalum.

Permanent magnets are generally made of alloys of.

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. Co

  2. Zn

  3. Mn

  4. Pb

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Correct Option: A

German silver alloy contains:

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. Zinc, silver and copper

  2. Nickel, silver and copper

  3. Germanium, silver and copper

  4. Zinc, nickel and copper

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Correct Option: D
Explanation:

German silver alloy contains $Cu\left( 25-30 \right)$%, $Zn\left( 25-35 \right)$% and $Ni\left( 10-35 \right) $%.

Which of the following metals are present in Devarda alloy?

chemistry d and f block elements solid solutions formation of complex compounds and constituent of catalysts general characteristics of first transition series

  1. $Cu$

  2. $Al$

  3. $Zn$

  4. $Ag$

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Correct Option: A,B,C
Explanation:

Devarda's alloy is  an alloy of aluminium (44% – 46%), copper (49% – 51%) and zinc (4% – 6%).

Devarda's alloy is used as reducing agent in analytical chemistry for the determination of nitrates after their reduction to ammonia under alkaline conditions.

Hence option A,B and C are correct.

Which of the following equation is the correct one?

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 + Hydrogen

  2. Amphoteric oxide / Hydroxide + alkali$\rightarrow$ Salt + Hydrogen

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

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

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Correct Option: D
Explanation:

Amphoteric oxide reacts with acid/alkali to produce salt and water not salt and hydrogen. Also, Metal and alkali react to give salt and liberate hydrogen not water. So, option D is correct.

Find the odd one with reasons [valency is not a criterion]: $Al(OH) _3, Pb(OH) _2, Mg(OH) _2, Zn(OH) _2$ :

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

  1. $Al(OH) _3$

  2. $Pb(OH) _2$

  3. $Mg(OH) _2$

  4. $Zn(OH) _2$

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Correct Option: C
Explanation:

$Mg(OH) _2$ is a basic hydoxide while rest are amphoteric hydroxides.

When aluminium hydroxide is reacted with excess sodium hydroxide, the soluble amphoteric 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. $\displaystyle { \left[ { Al\left( OH \right) } _{ 4 } \right] }^{ - }$

  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: A
Explanation:

$Al(OH) _3 + NaOH \rightarrow Na^+ [Al(OH) _4]^-$

 Aluminium hydroxide when reacted with excess sodium hydroxide, the soluble amphoteric compound  formed is sodium tetra hydroxoaluminate (III).