Answer:
The reactivity of metal is determined by the reactivity series. ... The metal which easily displaced aluminium will lie above in the series but that same element cannot displace sodium, so it will lie below in the series. Hence, from the series, we conclude that the unknown metal could be calcium or magnesium.
Explanation:
Hope this helps! :)
The simple trick which one can consider in such problem where it is asked for positron emission is :
<span>When the atomic number goes DOWN by one and mass number remains unchanged, then a positron is emitted.
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<span>a. </span>

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Here the atomic number decreases by one.
Similarly, options b and d are eliminated.
Option c is also not the answer.
For c, Count the atomic number on left side and compare it with right side. You will see it is 9 on left and 8 on right. Atomic no. did go down by 1. But the atomic mass is changed as well.
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Answer:
8.9 mg/l
Explanation: Temp doesnt matter so throw that out automatically then your equation is;
S1/P1=S2/P2
We are looking for S2 and that equation is;
S2=S1*P2/P1 and that is S2=22.25*1/2.5
A little bit of simple math and you get your answer: 8.9 mg/l
D an example of polygenic inheritance
ps this is more biology than chemistry
Carbon has a higher boiling point.