Tag: aluminium

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Multiple choice aluminium patterns and properties of metals chemistry

$Al$ is more reactive than iron but it is less easily corroded than iron because :

  1. it is a noble metal

  2. oxygen forms a protective oxide layer

  3. iron undergoes easily reaction with water

  4. iron formsmono and divalent ion
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Aluminum unlike iron ,does not corrode in moist conditions. Its surface is protected by layer of aluminium oxide. This prevents thealluminium to come in contact with air and oxygen. The layer of aluminium oxide do not vanish, unlike rust which can flake off the surface of iron and steel objects. So $Al$ is covered with a layer by the oxygen

Hence option B is correct.

Multiple choice aluminium patterns and properties of metals chemistry

A metal X reacts with aqueous NaOH solution to form Y and a highly inflammable gas. Solution Y is heated and $CO _2$ IS poured through it. Z precipitates out and $Na _2CO _3$ is formed. Z on heating gives $Al _2O _3$. Identify X, Y and Z.

  1. $Al-X$, $NaAlO _2 -Y$, $Al(OH) _3-Z$
  2. $Al _2O _3-X$, $NaAlO _2-Y$, $Al _2CO _3-Z$
  3. $Al _2O _3-X$, $[Na _2AlO _2]^+Oh^--Y$, $Al(OH) _3-Z$
  4. Al-X, $Al(OH) _3-Y$, $Al _2O _3-Z$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Solution:-

$X + NaOH(aq) \; \longrightarrow \; Y + \text{highly inflammable gas}$
$Y + CO _2 + H _2O \; \longrightarrow \; Z + {Na} _2CO _3$
$Z \; \xrightarrow [On \; heating] \; {Al} _2O _3$
${Al} _2O _3$ is formed when $Al{(OH)} _3$ is heated. 
$2Al{(OH)} _3 \; \xrightarrow [On \; heating] \; {Al} _2O _3 + 3H _2O$
Thus Z is $Al{(OH)} _3.$
When $NaAlO _2$ is heated and $ CO _2$ is poured through it, $Al{(OH)} _3$ precipitates out and $Na _2CO _3$ is formed.
$2NaAlO _2 + CO _2 + 3H _2O \; \longrightarrow \; 2Al{(OH)} _3 + {Na} _2CO _3$
Thus Y is $NaAlO _2$
When $Al$ reacts with aqueous $NaOH$ solution, it forms $NaAlO _2 \; and \; H _2 \; \text{(Highly inflammable gas)}$
$Al + NaOH(aq) \; \longrightarrow \; NaAlO _2 + H _2 \; \text{(highly inflammable gas)}$
Thus X is $Al$.
Hence, (A) is correct answer.

Multiple choice aluminium patterns and properties of metals chemistry

Thermite is a mixture of iron oxide and ___________.

  1. aluminium powder

  2. zinc powder

  3. iron turnings

  4. copper turnings
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Answer:- (A) Aluminium Powder
Thermite is the mixture of iron oxide $Fe _2O _3$ (rust) and aluminum powder. When it is ignited the aluminum powder reacts with the $O _3$ part of the rust in a highly exothermic reaction, the resulting product is molten iron. Thermite is commonly used in welding because the molten iron has the ability to seep into cracks in metal.

Multiple choice aluminium patterns and properties of metals chemistry

In the following reaction sequence,
$(A)+N _2 \xrightarrow { \triangle } (B) \xrightarrow {+H _2O} (C)+(D)$
white ppt. (C) is formed and gas (D) is evolved. White ppt. (C) dissolves in NaOH solution, while gas (D) gives white fumes in HCl. Thus, (A) is :

  1. B

  2. Al

  3. Ga

  4. C
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
$\underset{(A)}{2Al}+N _2 \rightarrow \underset{(B)}{2AlN}$
$\underset{(B)}{AlN}+3H _2O \rightarrow \underset{(C)}{Al(OH) _3}+\underset{(D)}{NH _3}$
Multiple choice aluminium patterns and properties of metals chemistry

Aluminium metal gets corroded or 'rusted' in places that are near to the sea, because the oxide film that protects it:

  1. is attacked by salt from sea water

  2. reacts with water

  3. is removed by sea water

  4. reacts with sand particles
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The presence of salt (or any electrolyte) in the water accelerates the reaction because it increases the conductivity of water, effectively increasing the concentration of ions in the water and so increasing the rate of oxidation (corrosion) of the metal.
Thusm aluminium metal is corroded in places that are near to the sea.
Multiple choice aluminium patterns and properties of metals chemistry

Serving trays for tea or food, made of aluminium, often have coloured finish. These finishes are formed when an electric current in passes, which creates an oxide of aluminium layer than absorbs dyes. This is called:

  1. Galvanizing

  2. Anodizing

  3. Sherardizing

  4. Annealing
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide finish. Aluminum is ideally suited to anodizing, although other nonferrous metals, such as magnesium and titanium, also can be anodized.

Hence option B is correct answer.

Multiple choice aluminium patterns and properties of metals chemistry

Metals rust when they come in contact with oxygen of the air that forms oxides and thereby destroys the metal. Which metal forms an oxide with oxygen, that protects it from further rusting:

  1. aluminium

  2. zinc

  3. iron

  4. copper
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Aluminium does not rust (corrode) because its surface is protected by a natural layer of aluminium oxide $\left( {Al} _{2}{O} _{3} \right)$. This prevents the metal below from coming into contact with air.
Multiple choice aluminium patterns and properties of metals chemistry

Which of the following materials can make cloth fire-proof?

  1. Copper oxide

  2. Aluminium sulphate

  3. Nickel chloride

  4. Magnesium sulphate
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Aluminium sulphate is used in producing fire proof textiles.

Multiple choice aluminium patterns and properties of metals chemistry

$Al {4}C _{3} + 12H _{2}O \rightarrow 3CH _{4} + $______

  1. $4 Al (OH) _{3}$
  2. $4 Al (OH) _{2}$
  3. $3 Al (OH) _{4}$
  4. $3 Al (OH) _{2}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

$ Al _4C _3 + 12H _2O \rightarrow 3CH _4 + 4Al(OH) _3$

When Aluminium carbide $Al _4C _3$ undergoes hydrolysis forms a methane along with a aluminium hydroxide as a product.

Multiple choice aluminium patterns and properties of metals chemistry

$Re{O} {3}$ possess conductance and appearance like that of ____

  1. $Al$
  2. $B$
  3. $Cu$
  4. $Pt$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
Rhenium trioxide is an inorganic compound with the formula ReO3.
It is a red solid with a metallic lustre, which resembles Cu (copper) in appearance and conductance.