Chemistry Test-3

Using ideal gas equation,

\(P V=n R T\)

\(P V=\frac{w}{M} R T\)

\(P=\frac{w}{M} \frac{R T}{V}\)

As per question the formula will be,

\(P=\left[\frac{w_{C}+w_{S_{2}}+w_{C S_{2}}}{M_{C}+M_{S_{2}}+M_{C S_{2}}}\right] \times \frac{R T}{V}\)

where,

\(P=\) total pressure \(=?\)

\(\mathrm{R}=\) gas constant

\(\mathrm{T}=\) temperature \(=1027^{\circ} \mathrm{C}=273+1027=1300 \mathrm{~K}\)

\(V=\) volume \(=13 \mathrm{~L}\)

\(w_{c}=\) mass of \(C=12 \mathrm{~g}\)

\(w_{S_{2}}=\) mass of \(S_{2}=64 \mathrm{~g}\)

\(w_{C S_{2}}=\) mass of \(C S_{2}=76 \mathrm{~g}\)

\(M_{c}=\) molar mass of \(\mathrm{C}=12 \mathrm{~g} / \mathrm{mole}\)

\(M_{S_{2}}=\) molar mass of \(S_{2}=64 \mathrm{~g} / \mathrm{mole}\)

\(M_{C S_{2}}=\) molar mass of \(C S_{2}=76 \mathrm{~g} / \mathrm{mole}\)

Now put all the given values in the above formula, we get:

\(P=\frac{12 g+64 g+76 g}{12 g / \text { mole }+64 g / \text { mole }+76 g / \text { mole }} \times \frac{R \times 1300 K}{13 L}\)

\(P=100 R\)

Therefore, the total pressure is, \(100 R\)

We know that:

\(\mathrm{NO} \longrightarrow \mathrm{N}_{2} \mathrm{O} ; \quad E^{\circ}=1.59 \mathrm{~V}\)

\(2 \mathrm{NO}+2 \mathrm{H}^{+} \longrightarrow \mathrm{N}_{2} \mathrm{O}+\mathrm{H}_{2} \mathrm{O} ; E^{\circ}=1.59\)

In basic medium,

\(2 \mathrm{NO}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{N}_{2} \mathrm{O}+2 \mathrm{OH}^{-}\)

Let \(E^{\circ}=x\)

Now, in alkaline medium,

\(\mathrm{H}_{2} \mathrm{O} \rightleftharpoons \mathrm{H}^{+}+\mathrm{OH}^{-}\)

\(\Rightarrow K=10^{-14}\)

or, \(2 \mathrm{H}_{2} \mathrm{O} \rightleftharpoons 2 \mathrm{H}^{+}+2 \mathrm{OH}^{-} ; K=10^{-28}\)

We know that, 

\(E^{\circ}=\frac{0.059}{n} \log K\)

\(=\frac{0.059}{2} \log 10^{-28}\)

\(=0.826\)

For standard potential,

\(E_{\text {acidic }}^{\circ}+E_{\text {basic }}^{\circ}=E_{\text {cell }}^{\circ}\)

\(\Rightarrow 1.59+x=0.826\)

\(\Rightarrow x=0.764\)

Peroxyacetyl nitrate (PAN) is used in the photochemical song.

Indigo is a vat dye. Dyeing with indignation was carried out in the wooden vats in the form of water-soluble indigotin-white.

IR active molecules are used in global warming.

Dioxins are used to burn the waste into ashes.

Given,

\(\mathrm{A}_{1}=0.5 \mathrm{~mol} \mathrm{~L}^{-1}\)

\(\mathrm{~A}_{2}=0.4 \mathrm{~mol} \mathrm{~L}^{-1}\)

\(\mathrm{t}=10\)min

For the reaction,

\(2 \mathrm{~A} \rightarrow\) products

Rate of reaction \(=\left[\frac{\Delta[\mathrm{A}]}{\Delta \mathrm{t}}\right]\)

\(=-\frac{1}{2}\left[\frac{\left[\mathrm{A}_{2}\right]-\left[\mathrm{A}_{1}\right]}{\mathrm{t}_{2}-\mathrm{t}_{1}}\right]\)

\(=-\frac{1}{2}\left[\frac{0.4-0.5}{10 \mathrm{~min}}\right]\)

\(=-\frac{1}{2}\left[\frac{-0.1}{10 \mathrm{~min}}\right]\)

\(=5 \times 10^{3} \mathrm{M} \) min \(^{-1}\)

The statement, "An atom has equal number of electrons and protons." will always be correct.

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral.

The conversion of atomic hydrogen into ordinary hydrogen is an exothermic reaction. Since atomic hydrogen is very unstable it readily combines with another hydrogen atom to form a hydrogen molecule that is highly stable hence energy is released.

The representation of the Galvanic cell is done as below:

Oxidation (left part) || Reduction (right part).

Aqueous elements have to be near the salt bridge in the representation. One has to remember that, in an electrochemical cell, reduction occurs at cathode and oxidation occurs at the anode.

Here in this question, option (A) satisfies the representation rules and thus, is the correct answer.

\({Zn}+2 {Ag}^{+} \longrightarrow {Zn}^{2+}+2 {Ag}\) can be represented as:

\(Z n_{(s)}|Z n_{(a q)}^{2+} \| A g_{(a q)}^{+}| A g_{(s)}\)

We know that:

The molar mass of oxygen \(=16\)

The molar mass of iron \(=55.85\)

Given:

Percentage of iron by mass \(=69.9 \%\)

Percentage of oxygen by mass \(=30.1 \%\)

Now,

Relative mass of iron in iron oxide \(=\frac{\text { Percentage of iron by mass }}{\text { At. mass of iron }}=\frac{69.9}{55.85}=1.25\)

Relative mass of oxygen in iron oxide \(=\frac{\text { Percentage of oxygen by mass }}{\text { At. mass of oxygen }}=\frac{30.1}{16}=1.88\)

Now,

Simplest molar ratio of iron to oxygen \(=1.25: 1.88=2: 3\)

Therefore the empirical formula of iron oxide is \({Fe}_{2} {O}_{3}\).

The substance not likely to contain CaCO₃ isCalcined gypsum.

• On heating, gypsum loses water and gives the hemihydrate (CaSO₄\(\cdot \frac{1}{2}\)H₂O) or the anhydrite. The hemihydrate known as Calcined gypsum / Plaster of Paris / stucco is an important building material.So, Calcined gypsum is not having calcium carbonate.
• Seashells are the exoskeletons of mollusks such as snails, clams, oysters and many others. Such shells have three distinct layers and are composed mostly of calcium carbonate (CaCO₃).
• Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally CaMg(CO₃)₂.
• A marble statue typically consists of calcium carbonate.

Among the following mixtures, dipole-dipole as the major interaction is present inAcetonitrile and acetone.

A carbocation will NOT show "Abstract a hydride ion to form an alkane" property.

A carbocation is a molecule in which a carbon atom has a positive charge and three bonds. Formerly, it was known as carbonium ion. Carbocation today is defined as any even-electron cation that possesses a significant positive charge on the carbon atom.

So, correct match

For the process to occur under adiabatic conditions, the correct condition is\(\mathrm{q=0}\).

When a thermodynamic system undergoes a change in such a way that no exchange of heat takes place between Systems and surroundings, the process is known as an adiabatic process. During the adiabatic process, there is no exchange of heat that takes place between the system and the surroundings.

The Element present in third period and seventeenth group of the periodic table is Chlorine and atomic number of Chlorine is 17.

Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature.

Given: Vapour pressure of liquid A, \(P_{A} =120~ mm\)

Vapour pressure of liquid B, \(P_{B} =180~ mm\)

Number of moles of liquid A,  \({n}_{{A}}=2\)

Number of moles of liquid B, \({n}_{{B}}=3\)

Therefore,

Mole fraction of liquid A,  \({X}_{{A}}=\frac{n_A}{n_A+n_B}\)\(=\frac{2}{5}\)

Mole fraction of liquid B,  \({X}_{{B}}=\frac{n_B}{n_A+n_B}\)\(= \frac{3}{5}\)

We know that: Vapor Pressure of solution, \({P}={X}_{{A}} {P}_{{A}}+{X}_{{B}} {P}_{{B}}\)

\(=\frac{2}{5} \times 120+\frac{3}{5} \times 180\)\(=48+108\)

\(P=156 {~mm} {~Hg}\)