If the standard reduction potential of a half-cell is positive, the reduction reaction is spontaneous when paired with a hydrogen electrode
<u>Explanation:</u>
- The relative standard reduction potential of the half-cell in which reduction occurs; more positive than the other half-cell.
- If the standard reduction potential of a half-cell is positive, the reduction reaction is spontaneous when paired with a hydrogen electrode.
- The reduction is a chemical process in which electrons are added to an atom or an ion; it always occurs accompanied by oxidation of the reducing agent.
- The reduction to happen the electrons gained by the material that is being decreased must be transported from the atoms of ions of a different material.
Answer:
Option (C).
Explanation:
The lac operon may be defined as the group of genes that are involved in the lactose metabolism of the <em>E.coli</em> bacteria. François Jacob and Jacques Monod was the first scientists to explain the mechanism of Lac operon.
The production of large amount of beta-galactosidase by the cells, the lactose level will decrease. This causes the elevation of the glucose level in the E.coli bacteria.
Thus, the correct answer is option (c).
Answer:
(C) HClO, pKa = 7.54
Explanation:
A buffer is a solution that can resist abrupt changes in pH when acids or bases are added. It is formed by two components:
- A weak acid and its conjugate base.
- A weak base and its conjugate acid.
In this case, acid and base are defined according to Bronsted-Löwry theory, which states that acids are substances that <em>release H⁺</em> and bases are substances that <em>accept H⁺. </em>Therefore, when an acid loses an H⁺ transforms into its conjugated base. For example, HF/F⁻ is a conjugate acid-base pair.
In buffers, when an acid is added, it reacts with the base to diminish its amount:
F⁻ + H⁺ ⇄ HF
Also in buffers, when a base is added, it reacts with the acid to diminish its amount:
HF + OH⁻ = F⁻ + H₂O
The optimum pH range of work of a buffer system (known as buffer range) is between 1 unit less and 1 unit more of pH than its pKa.
So, the buffer formed by HClO/ClO⁻ works optimally in the pH range 6.54-8.54. Since pH = 8.10 is in that interval, this would be the optimal choice.
Answer:
reaction B
Explanation:
From Arrhenius equation
k=A e-Ea/RT
Where
K= rate constant
Ea= activation energy
R= universal gas constant
T= temperature in kelvin
A= frequency factor
The higher the activation energy, the lower the value of e-Ea/RT. If A is constant for reaction A and B, then the reaction with lower activation energy will have a higher value of rate constant, k because e-Ea/RT will have a higher value. Hence reaction B having a greater activation energy will have a smaller value of rate constant k.