Chemistry Test-16

Reacting with water, a metal produces a base. Metals react with water and produce a metal oxide and hydrogen gas. Metal oxides that are soluble in water dissolve in it to further form metal hydroxide which are usually bases.

A bicycloalkene cannot have the formula of C₂H₆.

C₂H₆ has two degree of unsaturation (two H₂ less than saturated hydrocarbons), therefore it can be a diene, a cycloalkene or a bicycloalkane but it cannot be a bicycloalkene because it has three degrees of unsaturation.

The substance used in birth control pills is mestranol/novestrol.

Novestrol is a synthetic derivative of the natural estrogen estradiol. It is one of two estrogens currently used in oral contraceptive pills. The other, mestranol, is converted to novestrol before it is biologically active. Novestrol and norethindrone are used together as an oral contraceptive agent.

The 3-methyl ether of ethinyl estradiol. It must be demethylated to be biologically active. It is used as the estrogen component of many combination ORAL contraceptives.

Nylon 2-nylon 6comes under the category of biodegradable polymers.

Natural biodegradable polymers are called biopolymers. Polysaccharides, as starch and cellulose, represent the most characteristic family of these natural polymers. Other natural polymers as proteins can be used to produce biodegradable materials. These are the two main renewable sources of biopolymers.

According to Dalton's law of partial pressure, the total pressure exerted by a gaseous mixture is equal to the sum of the partial pressures of the individual gases in the mixture. The partial pressure is defined as the pressure each gas would exert if it alone occupied the volume of the mixture at the same temperature.

For instance a mixture has gas X and Y then the total pressure will be the sum of partial pressures of X and Y.

Let t be the time for potential of metal sphere to rise by \(1.0 V\). Then up to this time \(\beta\) particles emitted from sphere are

\(N =\left(6.25 \times 10^{10}\right) \times t\)

Number of \(\beta\) particles escaped in this time are

\(N _{ e }=(80 / 100) \times\left(6.25 \times 10^{10}\right) t =\left(5 \times 10^{10}\right) t\)

Thus, charge acquired by the sphere in \(t s\)

\(Q =\left(5 \times 10^{10} t \right)\left(1.6 \times 10^{-19}\right)=\left(8 \times 10^{-9} t \right) \text { coulomb }\)

(emission of \(\beta\) particle leads to a charge e on the metal sphere)

The capacitance \(C\) of a metal sphere is given by

\(C =4 \pi \varepsilon_{0} \times r =\left(\frac{1}{9 \times 10^{9}}\right) \times\left(\frac{10^{-3}}{2}\right)=\frac{10^{-12}}{18} F\)

we know that \(Q = C \times V \Rightarrow\left(8 \times 10^{-9}\right) t =\left(\frac{10^{-12}}{18}\right) \times 1 \Rightarrow t =6.95 \times 10^{-6} sec = 6.95 \mu sec \)

(here \(V =1\) volt)

Factors affecting Brownian motion:

• Brownian motion is affected by any factor that affects the motion of particles.
• Sol particles in a colloid are continuously bombarded by the molecules of the dispersion medium and thus show zig-zag motion. This Zig-zag motion is called the Brownian motion.
• Brownian motion is observed in the particle size of 2-5 microns.
• Temperature influences the speed and kinetic energy of the particles, and thus Brownian motion is affected by temperature.
• The motion of particles depends on their size and thus influences Brownian motion.
• As the number of particles increases, the number of collisions also increases, and thus Brownian motion is disrupted.
• The energy of the light beam depends on the wavelength of the light as E = hc/λ, so as the energy of light wavelength changes, the energy of the sol particles also changes which in fact alters the Brownian motion.
• Thus, Brownian motion is dependent on the intensity of light wavelength used.
• The Brownian motion also depends on the density and viscosity of the dispersed phase and the density and viscosity of the dispersed medium.

So, the incorrect statement about the Brownian movement is it is independent of the wavelength of light used.

Apart from several gamma particles, total five alpha and three beta particles are emitted. \(231,^{231}Ac _{89}\) into \({ }^{221} Pb _{82}\) this converts.

\({ }^{231} Ac _{89} \rightarrow{ }^{82} Pb _{82}\)

Note: When an alpha particle is emitted, the atomic number decreases by 2 and the mass number decreases by 4 . When a beta particle is emitted, the atomic number increases by 1 and the mass number remains unchanged.

The atomic number of daughter nucleus \(=89-5 \times 2+3 \times 1=82\)

The mass number of daughter nucleus \(=231-5 \times 4=211\)

So the correct answer is\({ }^{211} P b_{82}\).

Henry’s law of solubility can be expressed by the following formula:

\(S_g=k P_g\)

Here, \(S_g\) is solubility of gas, k is the Henry’s constant and \(P_g\)is the partial pressure.

Thus, according to Henry's law of solubility, on increasing the pressure of gas above the liquid, concentration of the gas in solution also increases which means solubility of gas in liquid increases with increase of pressure.

Moreover, solubility of a gas in liquid also increases with the lowering of temperature. Actually, increase in temperature increases the kinetic energy as well. The higher kinetic energy leads to more motion/movement in the molecules thereby dissociating the intermolecular bonds and ultimately escaping from the solution. Thus, solubility of gas in liquid decreases with increase of temperature and increases with decrease in temperature.

Hence, Solubility of a gas in liquid increases with increase of pressure and decrease of temperature.