NEET Practice Questions (MCQs) with Answers & Solutions

(A) From salts of magnesium, magnesium cannot be extracted by other chemical methods as magnesium itself acts as a reducing agent and Mg obtained at the cathode during electrolysis of its salt solution, reacts with water forming Mg ${\left(OH\right)}_2.$

 At cathode $M{g}^{2+}+2e^{-}\to Mg;$ At anode $2C{l}^{-}\to C{l}_{{}^2}+2e^{-}$

(A) Randomness increases on changing the phase from soilid to liquid or from liquid to gas.

(A) $Au\left(S\right)\stackrel{O^2}{\to }A{u}^{+}\left(aq.\right)$

     $A{u}^{+}+2C{N}^{-}\left(aq.\right)\to {\left[Au{\left(CN\right)}_2\right]}^{-}$ soluble complex.

(A)

 Cast iron contains 3% carbon.

Pig Iron and its properties:

• Pig Iron is a basic raw material for all irons and produced from a blast furnace.

• It contains Carbon percentage equal to 3-4%

• Pig Iron from ore contains three basic forms of Iron:
  1. Cast iron (Made from Cupola furnace)
  2. Wrought Iron (Made from Pudding furnace) 
  3. Steel (Made from Bessemer converter)

Wrought Iron and its properties:

• Wrought Iron is a mechanical mixture of pure iron and silicate slag

• Its Carbon percentage is 0.02% to 0.03%

• Wrought Iron is never cast or difficult to cast

• Wrought Iron is having high ductile, corrosion resistant, fatigue resistant

• It is having Tensile strength: 3380-3500 kg per square centimeter and 2530-2670 kg per square centimeter in transverse direction

• Wrought Iron's melting point: 1510 degree C, Weight – 7680 kg per meter cube.

• Wrought Iron's Poisson's ratio: 0.3

Malleable Cast Iron and its properties:

• Malleable Cast Iron is obtained from hard & brittle white iron., through a controlled heat treatment conversion process.

• Malleable Cast Iron is having Carbon percentage : 2 % to 3 %

• Malleable Cast Iron having material properties like High yield strength, ease of machinability, corrosion resistance and high young modulus

• It is having Low coefficient of thermal expansion and high wear resistance & damping vibration.

• Shrinkage Allowance for this Iron is 1.5 mm / 100mm

• Malleable Cast Iron is used to make Crank-shaft, rail road, universal joint etc.

(A) Upper most layer of pure molten aluminium, middle layer of molten fluorides of $N{a}^{+}$, $B{a}^{+2}$ and $A{l}^{+3}$ and lower layer of Molten impure aluminium have different densities.

(C) Assertion : It lowers the fusion temperature of $MgC{l}_2$ and provide conductivity to the electrolyte.

    Reason : $MgC{l}_2$.$6H_{2}O$  is calcined in a stream of dry HCI gas to have anhydrous $MgC{l}_2$. In
absence of dry HCI, It forms $MgOC{l}_2\left(MgO.MgC{l}_2\right)$ because of hydrolysis.

(a) PbO₂ does not contain -O-O- bond. It is lead dioxide.

 $\stackrel{..}{{\mathrm{PH}}_3}$+H^+_$\to$ ${\mathrm{PH}}_4^{+}$

According to Drago's rule lone pair on phosphorous resides in almost pure s- orbital, hence due to non directional nature, its overlapping tendency is greatly reduced in comparison to a lone pair present in hybrid orbital, which is directional as present in $\stackrel{..}{{\mathrm{NH}}_3}$

I₂ + 10HNO₃  $\to$ 2HIO₃ + 10NO₂ + 4H₂0

The partial hydrolysis of one mole of peroxodisulfuric acid (H₂S₂O₈) produces one mole of sulfuric acid (H₂SO₄) and one mole of peroxomonosulfuric acid (H₂SO₅). The reaction is: H₂S₂O₈ + H₂O → H₂SO₄ + H₂SO₅.