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

Which of the following set of metals can form alloy.

  1. $Cu$ and $Au$
  2. $Li$ and $Na$
  3. $Fe$ and $Hg$

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
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.

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

Which of the following metals are present in Devarda alloy?

  1. $Cu$
  2. $Al$
  3. $Zn$
  4. $Ag$
Reveal answer Fill a bubble to check yourself
A,B,C Correct answer
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.

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

Which of the following equation is the correct one?

  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
Reveal answer Fill a bubble to check yourself
D Correct answer
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.

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

When aluminium hydroxide is reacted with excess sodium hydroxide, the soluble amphoteric compound is formed. Mark the correct formula. 

  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. $\displaystyle { \left[ { Al\left( OH \right) } _{ 7 } \right] }^{ 4- }$
Reveal answer Fill a bubble to check yourself
A Correct answer
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).