Answer : The correct option is, (4) 6.0 mol
Explanation :
The given balanced chemical equation is,

In this reaction, lead undergoes reduction and chromium undergoes oxidation.
Oxidation reaction : It is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction : It is the reaction in which a substance gains electrons. In this oxidation state decreases.
Half reactions of oxidation-reduction are :
Oxidation : 
Reduction : 
From the reduction reaction, we conclude that 6 moles of electrons gained by the 3 moles of lead ions.
Hence, the correct option is, (4) 6.0 mole
Answer:
The electrophile is the hydroxide free radical
Explanation:
The hydroxylation of benzene and benzene derivatives using hydrogen peroxide proceeds in the presence of an acidic catalyst. The electrophile in this reaction is the hydroxyl free radical generated in an initial step of the reaction.
This is actually a free radical reaction. The hydroxyl radical previously generated reacts with the benzene ring to yield a radical that undergoes further rearrangement to yield the product phenol. The intermediate, shown as part of this reaction mechanism (refer to image attached) is a specie in which the odd electron is delocalized over the entire benzene ring. Loss of a proton completes the reaction mechanism yielding the corresponding phenol.
<span>They utilize and make use of the scientific method in order to have clear basis and evidence for their investigations. Research method is always used to answer every scientific inquiry and in gaining evidential data or knowledge. The scientific method has the following process or at least undergoes the process of
1. Observation</span>
<span>2. Hypothesis </span>
<span>3. Experimentation </span>
<span>4. Interpretation of data </span>
<span>5. Evaluating the data </span>
<span>6. Passing and recording the data </span>
<span>These steps are crucial and the empirical data that these scientists obtain are very important to keep that is why research paper, thesis and dissertations exists.<span>
</span></span>
Answer:
Gradual refinement
Explanation:
Gradual refinement is the process whereby the System Development Life Cycle goes through a series of development stages, each stage/phase refining the previous one.