Chemistry Test - 1

Group number 3 to 12 are called transition metal.

The elements occurring in the group 3 to 12 are named as transition metals because they are metallic elements that form a transition between the main group elements, which occur in groups 1 and 2 on the left side, and groups 13–18 on the right side of the periodic table.

The reaction of benzene with chlorine in the presence of iron gives chlorobenzene.

When benzene reacts with chlorine gas in the presence of iron catalyst such as iron (III) chloride , it displaces one hydrogen from the ring to chlorine atom and leads to the formation of chlorobenzene.

The reaction takes place as follows:

If the lone pair donating tendency on oxygen is reduced, nucleophilicity reduced. This is because the electron density of larger atoms is more readily distorted since the electrons are further from the nucleus.

\(\mathrm{H}_2 \mathrm{O}=\) Neutral molecule

\(\begin{aligned} & \mathrm{CH}_3 \mathrm{SO}_3{ }^{\ominus}=\mathrm{CH}_3 \mathrm{~S}-\mathrm{O}^{-}=\text {Charged ion } \\ & \mathrm{CH}_3 \mathrm{COO}^{\ominus}=\mathrm{CH}_3-\mathrm{C}^{-}-\mathrm{O}^{-}=\text {Charged ion }\end{aligned}\)

 \(\stackrel{\ominus}{\mathrm{O}} \mathrm{H}\) Charged ion

Thus, the increasing order of nucleophilicity is:

\(\mathrm{H}_2 \mathrm{O}<\mathrm{CH}_3 \mathrm{SO}_3^{\ominus}<\mathrm{CH}_3 \mathrm{COO}^{\ominus}<\mathrm{OH}\)

The band spectrum is caused by molecules. The energy levels of molecules are so close to each other that they combine to form a band. The valence band and conduction band are two types of bands. Electron transition between these two bands forms band spectrum.

The total number of octahedral voids per atom present in a cubic close packed structure is 4. Besides the body centre, there is one octahedral void at the centre of each of the 12 edges. 

It is surrounded by six atoms, four belonging to the same unit cell (2 on the corners and 2 on face centres) and two belonging to two adjacent unit cells. Since each edge of the cube is shared between four adjacent unit cells, so is the octahedral void located on it. 

Only \(\frac{1}{4}\)th of each void belongs to a particular unit cell. Thus, in cubic close packed structure, octahedral void at the body-centre of the cube is 1.

12 octahedral voids located at each edge and shared between four unit cells

\(=12\times\frac{1}{4}=3\)

Total number of octahedral voids = 4

We know that in ccp structure, each unit cell has 4 atoms. Thus, the number of octahedral voids \(=\frac{4}{4}=1\).

Thermodynamics is not concerned about the rate at which a reaction proceeds.

Thermodynamics tells us about the feasibility, energy changes, and extent of a chemical reaction. It does not tell us about the rate of the reaction. The kinetics of the reaction are concerned about the rate at which the reaction proceeds.

We know that:

Hydrogen exist as \(H_{2}\) and oxygen as \(O_{2}\).

1 mole of all gases occupy \(22.4 \mathrm{~L}\) volume at NTP.

Moles in 2 g hydrogen \(=\frac{\text { mass }}{\text { molar mass }}\) 

\(=\frac{2}{2}\)

\(=1 \mathrm{~mol}\)

\(=22.4 \mathrm{~L}\)

Moles in 32 g oxygen \(=\frac{\text { mass }}{\text { molar mass }}\)

\(=\frac{32}{32}\)

\(=1 \mathrm{~mol}\)

\(=22.4 \mathrm{~L}\)

Then, total volume occupied \(=22.4+22.4\)

\(=44.8 \mathrm{~L}\)

The correct name of \(\left[ Pt \left( NH _{3}\right)_{4} Cl _{2}\right]\left[ P tCl _{4}\right]\) is: Tetraaminedichloro platinum (IV) tetrachloro platinate(II)

First, we have to write the cationic part, of the coordinate compound

Here, the ligands are Amine and Chloride. Since there are 4 amine groups we'll name it as tetramine and 2 chloride groups will be named as dichloro. Also, we have platinum metal as the central metal atom in a cation, and it's oxidation state is +4 .

Now for the other (anionic part):

Here the ligand is chloride. Since there are 4 chlorides so we'll call it tetrachloride. We have the central metal atom as platinum again, but since it is in the anionic coordination sphere.

Soaps are sodium or potassium salts of long-chain of carboxylic acids.

Sodium salts of fatty acids are called hard soaps and potassium salts of fatty acids are called soft soaps.

Soaps are sodium or potassium salts of long-chain fatty acids.

Alcohol carries one hydroxyl functional group (at least) which is bound to a saturated carbon atom. The molecular formula is C_nH_2n+1OH.

Aldehydes carry a functional group with the structure − CHO. In this, a carbon atom shares a double bond with an oxygen atom, a single bond with a hydrogen atom, and a single bond with another atom. 

Esters are derived from carboxylic acids (-COOH group). The hydrogen is replaced by a hydrocarbon group in esters.

Terbium (Z \(= 65\)) is a lanthanide and all others are actinoids.

• Lanthanides have atomic numbers from \(58\) to \(71\). 
• Actinides have atomic numbers from \(90\) to \(103\).
• The lanthanides and actinides form a group that appears almost disconnected from the rest of the periodic table. 
• This is the f- block of elements, known as the inner transition series. This is due to the proper numerical position between Groups \(2\) and \(3\) of the transition metals.