<u>Answer:</u> The elevation in boiling point is 1.024°C.
<u>Explanation:</u>
To calculate the elevation in boiling point, we use the equation:

where,
i = Van't Hoff factor = 2 (for NaCl)
= change in boiling point = ?
= boiling point constant = 
m = molality = 1.0 m
Putting values in above equation, we get:

Hence, the elevation in boiling point is 1.024°C.
The correct answer is
<span>c) very small and very large
Let's see this with a few examples:
1) if we have a very small number, such as
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<span>we see that we can write it easily by using the scientific notation:
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<span>2) Similarly, if we have a very large number:
</span>

<span>we see that we can write it easily by using again the scientific notation:
</span>

<span>
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the answer is concave lens