Answer:
E) 2.38
Explanation:
The pH of any solution , helps to determine the acidic strength of the solution ,
i.e. ,
- Lower the value of pH , higher is its acidic strength
and ,
- Higher the value of pH , lower is its acidic strength .
pH is given as the negative log of the concentration of H⁺ ions ,
hence ,
pH = - log H⁺
From the question ,
the concentration of the solution is 0.0042 M , and being it a strong acid , dissociates completely to its respective ions ,
Therefore , the concentration of H⁺ = 0.0042 M .
Hence , using the above equation , the value of pH can be calculated as follows -
pH = - log H⁺
pH = - log ( 0.0042 M )
pH = 2.38 .
<span>The Persian Wars mark an important turning point not only in Greek history but, indeed, in the course of all European civilization. First and foremost, because of its victory Greece was saved from the threat of external rule and could develop on its own. Handed this independence, the Greeks chose to follow a path which forever changed the course of modern life. Without their success in this conflict, they would, no doubt, never have had the liberty, means or conviction to invent, discover or create all they did: not just history but philosophy, science, drama, art, architecture, indeed most of the cornerstones of modern civilization.
Another consequence of this victory, less immediate but equally important, was that it prevented the Persians from dominating the lands to the west of Greece—as noted above, it's likely the fertile fields of Italy and Sicily, not the rough dust of Greece, were the real target of Xerxes' imperial designs—and there a tiny settlement called Rome had just begun to sprout, at that moment hardly a dot on the map, but it would later develop into a crucial player in the history of the West. Rome won freedom, too, in the Persian Wars, without ever fielding a single fighter. It's impossible to imagine how vastly different our world would be if Persia had conquered or exterminated the Romans before they'd ever had a chance to grow.
Thus, the Greeks laid the groundwork for later Western culture, and Herodotus the foundation for understanding it. If so many of his facts look suspect or even prove incorrect, if he sometimes seems to set speculation and scandal over sober criticism and science, before condemning him we should recall that he founded this entire enterprise called history, a discipline which still bears the name he gave it. His critics should also bear in mind it's only because Herodotus set us on this path that we can even scorn his methods in the first place. To this most uncommon "common man," we owe an enormous collective debt.</span>
In a flame photometric analysis, salt solution is first vaporized using the heat of flame, followed by this electrons from valance shell gets excited from ground state to excited state. Followed by this de-excitation of electron bring backs electrons to ground state. This process is accompanied by emission of photon. The photon emitted is characteristic of an element, and number of photons emitted can be used for quantitative analysis.
<span>Following are the investigative question that you can answer by doing this experiment.
</span>1) What information can be obtained from the colour of flame?
2) <span>State the relationship between wavelength, frequency, and energy?
</span><span>3) Can you identify the metal present in unknown sample provided?
4) How will you identify amount of metal present in sample solution?
5) </span><span>Why do different chemicals emit light of different colour?</span><span>
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