Chemistry Test-13

Crystallization is a process where solute particles come together to form a solid crystal lattice. It typically occurs when a solution becomes saturated, meaning it contains the maximum amount of solute that can dissolve in the solvent at a given temperature.

The following reaction describes the rusting of iron:

\(4 \mathrm{Fe}+3 \mathrm{O}_{2} \rightarrow 4 \mathrm{Fe}^{3+}+6 \mathrm{O}^{2-}\)

Here, metallic iron loses electrons to form \(\mathrm{Fe}^{3+}\). Hence, it has been oxidised. It is an example of redox reaction not just oxidation reaction. Iron is oxidised and oxygen is reduced in this reaction.

A thermodynamic state function is a quantity whose value is independent of the path. Its value depends on initial and final states and is independent of the path followed. Functions like \(p, V, T\), etc. depend only on the state of a system and not on the path. A state function describes the equilibrium state of a system.

We know that \(22,400 cm ^3\) of \(H _2\) means 1 mole of \(H _2\).

Now, we know that \(2 H ^{+}+2 e^{-} \rightarrow H _2\)

Hence, for the production of 1 mole of \(H _2\), two moles of \(e^{-}\)are required.

And, one mole of \(e^{-}\)constitutes \(96500 C\)

Hence, charge or electricity required \(=96500 \times 2=\) \(193000 C\)

Electrophoresis:

• The coagulation of lyophobic sols can be done by electrophoresis where the colloidal particles move towards oppositely changed electrodes which gets discharged and forms precipitate. So, option (C) is correct.

Colloidal medicines:

• Medicines are more effective in colloidal state because colloids have a larger surface area. Thus, they get easily assimilated, absorbed and digested. So, option (a) is wrong.

Addition of alum:

• Alum is used in the form of Aluminium Sulphate (usually) to remove particulates in water through flocculation to remove solids and some ions and allow them to be filtered or settled. This process is a part of water treatment process. Excess of alum can make water unfit for drinking but in terms of excess is not mentioned in the option. Thus, option (B) is wrong.

Brownian motion:

• The viscosity is also inversely proportional to the speed of Brownian motion. So, lesser the viscosity, faster the motion. Thus, option (D) is wrong.

Chlorinebelongs to third period and \(17\)th group of the periodic table.

The third period contains eight elements: sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, and argon. Halogens start from the second period.Counting the periods and matching it with the periods of that of halogens, we find that period \(3\) has Chlorine.The electronic configuration of chlorine is \(1 s^2 2 s^2 2 p^6 3 s^2 3 p^6\).

Step 1: Metal when exposed to air for a long time undergo corrosion. During corrosion, the metal on the surface undergoes a chemical reaction forming a new compound that changed the property of the metal at the surface. Rusting of iron is a common phenomenon of corrosion.

Step 2: Copper is a metal. Similarly. copper when kept open in air for a long time it slowly loses its shining brown surface and gains a green coating because of corrosion. During corrosion of copper, it reacts with carbon dioxide gas and moisture present in the air. This is called tarnishing of copper. The reaction is as follows.

\(2 \mathrm{Cu}+\mathrm{H}_2 \mathrm{O}+\mathrm{CO}_2+\mathrm{O}_2 \rightarrow\mathrm{Cu}(\mathrm{OH})_2+\mathrm{CuCO}_3\)

Step 3: Different methods are available to prevent corrosion. Corrosion of copper can be protected by coating it with a thin layer of tin.

Unsaturated hydrocarbons are hydrocarbons that have double or triple covalent bonds between adjacent carbon atoms.

The term "unsaturated" means more hydrogen atoms may be added to the hydrocarbon to make it saturated (i.e. consisting of all single bonds).

The example of the unsaturated compound is alkenes and alkynes, as well as branched chains and aromatic compounds.

PDI for natural polymers is generally close to 1.

For natural polymers, PDI (Polydispersity Index) is generally equal to 1, which means that they are monodisperse. Such polymers are more homogeneous.

Use of chemicals for therapeutic effect is called chemotherapy.

Any medication consumed by us as a human can actually have two kinds of effects – therapeutic effects and side effects.

Chemotherapy: We should know that it is a chemical drug treatment. It is a very aggressive treatment. In this type of treatment, chemicals are used to destroy growing cells in the human body. It’s usually used to treat cancer, as cancer cells grow and divide faster than other cells. We use these chemicals in chemotherapy, to lower the total number of cancer cells in your body and it reduces the likelihood of cancer spreading. These chemicals target tumours and shrink their size.