Oxygen<span> is a </span>chemical element<span> having a symbol </span>O<span> and having an </span>atomic number<span> 8.
Oxygen is a pure substance , and it is not a mixture or solution, Niether it is a compound ... Instead , it forms chemical compounds by reacting with other elements.
So , according to above explanation ,
A. A pure substance , is the correct answer.</span>
Answer:
Explanation:The scientific method is an empirical method of acquiring knowledge that has characterized the development of science since at least the 17th century. It involves careful observation, applying rigorous skepticism about what is observed, given that cognitive assumptions can distort how one interprets the observation. It involves formulating hypotheses, via induction, based on such observations; experimental and measurement-based testing of deductions drawn from the hypotheses; and refinement (or elimination) of the hypotheses based on the experimental findings. These are principles of the scientific method, as distinguished from a definitive series of steps applicable to all scientific enterprises.[1][2][3]
Though diverse models for the scientific method are available, there is in general a continuous process that includes observations about the natural world. People are naturally inquisitive, so they often come up with questions about things they see or hear, and they often develop ideas or hypotheses about why things are the way they are. The best hypotheses lead to predictions that can be tested in various ways. The most conclusive testing of hypotheses comes from reasoning based on carefully controlled experimental data. Depending on how well additional tests match the predictions, the original hypothesis may require refinement, alteration, expansion or even rejection. If a particular hypothesis becomes very well supported, a general theory may be develope
Answer : The molarity of 
solution is, 0.352 M
Explanation :
First we have to calculate the moles of 
Molar mass of = 278.1 g/mol
Now we have to calculate the moles of 
The balanced chemical equation is:
From the balanced reaction we conclude that
As, 1 mole of produced from 1 mole of
So, 0.07041 mole of produced from 0.07041 mole of
Now we have to calculate the molarity of
Therefore, the molarity of solution is, 0.352 M
Answer:
Option D, ketone
Explanation:
Since Jones reagent (CrO3/H2SO4) is a strong oxidizing agent and oxidize the secondary alcohol to ketone.
Example , isopropanol gets oxidized to propanone.
Primary Alcohol gets oxidized to Carboxylic acids.
