Chemistry Test - 2

The oxidative rusting of iron under Earth's atmosphere is slow reaction.

The reaction rate (rate of reaction) or speed of reaction for a reactant or product in a particular reaction is intuitively defined as how fast or slow a reaction takes place. For example, the oxidative rusting of iron under Earth's atmosphere is a slow reaction that can take many years.

The coordination number of chromium in \(\mathrm{K}_{3}\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]\) is 6 . There are three oxalate groups attached to the central ion in the given compound, but since oxalate is a didentate ligand, there are a total of 6 donor atoms to which the metal is directly bonded. Thus, the \(\mathrm{CN}\) of \(\mathrm{Cr}\) in \(\mathrm{K}_{3}\left[\mathrm{Cr}\left(\mathrm{C}_{2} \mathrm{O}_{4}\right)_{3}\right]\) is 6 .

Coordination number is also known as the secondary valence of a central metal ion in a complex and is defined as the number of donor atoms it is directly bonded to. Hence, the coordination number is a quantity associated with the metal ion.

In this reaction Mixture of \(1,2-\) dibromopropane and \(1\) -bromo\(-2\) chloropropane is formed as follows:

The usage of hydrogen as a low-carbon energy source, such as gasoline as a transport fuel, it is referred to as "Hydrogen economy". The basic principles of Hydrogen economy are:

(i) Storage of energy in the form of liquid or gaseous dihydrogen.

(ii) transportation of energy in the form of liquid or gaseous dihydrogen.

Given, \( \Delta G_{298}^{\circ}=-4650 J / mol\)

We know that,

\(\Delta G^{\circ}=-R T \ln K\)

\(\ln K=-\frac{\Delta G^{\circ}}{R T}\)

\(\ln K=\frac{4650}{8.314 \times 298}=1.877\)

Here, \(K_{i}=6.58, \Delta H^{\circ}=-3640 J / mol\)

\(T_{1}=298 K , T_{2}=95^{\circ} C =368 K\)

Putting values,

\(\ln \left(\frac{K_{2}}{6.58}\right)=\frac{3640}{8.314} \times\left(\frac{1}{368}-\frac{1}{298}\right)\)

\(\ln \left(\frac{K_{2}}{6.58}\right)=-0.279\)

\(K_{2}=4.94\)

Let the oxidation number of \(M n\) be \(x\) in all the compounds.

We know that:

Oxidation state of \(K=+1, O=-2\).

(A) \(K M n O_{4}: 1+x+4 \times(-2)=0\)

\(x=+7\)

(B) \(K_{2} M n O_{4}: 2 \times 1+x+4 \times(-2)=0\)

\(x=+6\)

(C) \(M n O_{2}: x+2 \times(-2)=0\)

\(x=+4\)

(D) \(M n_{2} O_{3}: 2 x+3 \times(-2)=0\)

\(x=+3\)

Therefore, highest oxidation number of \(\mathrm{Mn}\) is \(+7\) in \(\mathrm{KMnO}_{4}\).

The solutions which obey Raoult’s law over the entire range of concentration are known as ideal solutions. 

The ideal solutions have two other important properties. The enthalpy of mixing of the pure components to form the solution is zero and the volume of mixing is also zero, i.e.,

For ideal solution, 

\(\Delta_{\operatorname{mix}} \mathrm{H}=0\)

\(\Delta_{\operatorname{mix}} \mathrm{V}=0\)

Eka is a prefix used to designate the first element of the same family in the periodic table beyond the one to whose name it is prefixed, as Eka manganese.

• Eka silicon - Ge (germanium)
• Eka aluminium - Ga (gallium )
• Eka manganese - Tc (technetium) 
• Eka boron – Sc (scandium)

Such a large difference in electronegativity shows that Caesium is electropositive while Fluorine is electronegative in nature. So, Caesium can donate an electron to Caesium which can accept it. So, they form ionic bond or electrovalent bond.

The main cause of acidity in the stomach is release of extra gastric acids which decrease the pH level. 

• Gastric acid is a digestive fluid formed in the stomach and is composed of hydrochloric acid \((\mathrm{HCl})\), potassium chloride \((\mathrm{KCl})\) and sodium chloride \((\mathrm{NaCl})\).
• If gastric acid is released in the stomach, the \(\mathrm{pH}\) level decreases and thereby increasing acidity in the stomach.