Ncert Solutions Chemistry Class 12th
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10 months agoContributor-Level 10
The iron obtained from blast furnaces is known as pig iron. It contains around 4% carbon and many impurities such as S, P, Si, Mn in smaller amounts.
Cast iron is obtained by melting pig iron and coke using a hot air blast. It contains a lower amount of carbon (3%) than pig iron, cast iron is extremely hard and brittle.
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10 months agoNew answer posted
10 months agoContributor-Level 10
To separate alumina from silica in bauxite ore associated with silica, firstly, the powdered ore is digested with a concentrated NaOH solution at a temperature of 473 – 523K and 35 – 36 bar pressure. This results in the leaching out of alumina (Al2O3) as sodium aluminate and silica (SiO2) as sodium silicate leaving the impurities behind.
Al2O3 (s) + 2NaOH (aq) + 3H2O (l) → 2 Na [Al (OH)4] (aq)
SiO2 + 2NaOH (aq)→ Na2SiO3 (aq) + H2O (l)
After this, CO2 gas is passed through the resultant solution to neutralize the alumina present in the solution, this results in the precipitation of hydrated samples of alumina. To include precipitat
New answer posted
10 months agoContributor-Level 10
Nickel is refined by Mond's process. In this process, nickel is heated in the presence of carbon monoxide to form nickel tetracarbonyl, which is a volatile complex.
New answer posted
10 months agoContributor-Level 10
7.52
Oxygen is smaller in size as compared to sulphur. Due to its smaller size, it can effectively form p – p bonds and form O2 [O = O] molecule. Also, the intermolecular forces in oxygen are weak van there Wall's, which cause it to exist as a gas.
On the other hand, sulphur does not form M2 molecule but exists as a puckered structure held together by strong covalent bonds. Hence, it is a solid.
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10 months agoContributor-Level 10
The components selected for the stationary phase should have different solubility's in the phase, only then it is selected as the stationary phase. Hence, different components have different rates of movement through the stationary phase; as a result, can be separated from each other.
New answer posted
10 months agoContributor-Level 10
7.51
The elements of group 16 are collectively called chalcogens.
[i]. Elements of group 16 have six valence electrons each. The general electronic configuration of these elements is ns2 np4, where n varies from 2 to 6.
[ii]. Oxidation state: As these elements have six valence electrons [ns2np4], they should display an oxidation state of -2. However, only oxygen predominantly shows the oxidation state of -2 owing to its high Electronegativity. It also exhibits the oxidation state of -1 [H2O2], zero [O2], and +2 [OF2].
However, the stability of the -2 oxidation state decreases on moving down a group due to a decrease in the El
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10 months agoContributor-Level 10
Chromatography is a term used for numerous laboratory techniques for the separation of mixtures. The term is derived from Greek word 'chroma' meaning 'color' and 'graphein' meaning 'to write'. Chromatographic techniques are based on the principles that different components are adsorbed differently on an adsorbent. There are various chromatographic techniques used such as paper chromatography, column chromatography, gas chromatography, etc.
New answer posted
10 months agoContributor-Level 10
During the roasting of pyrite ore, a mixture of FeO and Cu2O is obtained.
2 CuFeS2 + O2→ Cu2S + 2 FeS + SO2
2 Cu2S + 3 O2 → 2 Cu2O + 2 SO2
2 FeS + 3 O2 → 2 FeO + 2 SO2
The role of silica in the metallurgy of copper is to remove the iron oxide obtained during the process of roasting as 'slag'. If the sulphide ore of copper iron, then silica (SiO2) is added as a flux before roasting. Then, FeO combines with silica to form silicate, FeSiO3 (slag).
FeO + SiO2→ FeSiO3 (slag)
New answer posted
10 months agoContributor-Level 10
7.50
Phosphorous Pentachloride [PCl5] cannot act as reducing agent because in the PCl5, the oxidation state of chlorine is +5 and it is not possible for Chlorine to increase its oxidation state beyond +5 but it can very easily act as an oxidizing agent because it can easily reduce its oxidation state from +5 to +3.
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