Chlorine react vigorously with hydrogen in the present of sunlight because chlorine has a great attraction for hydrogen's electron. During the reaction, chlorine and hydrogen will donate one electron each from their valence electrons which will be shared equally by both elements, thus forming a covalent bond.
Answer:- As per the question is asked, 35.0 moles of acetylene gives 70 moles of carbon dioxide but if we solve the problem using the limiting reactant which is oxygen then 67.2 moles of carbon dioxide will form.
Solution:- The balanced equation for the combustion of acetylene is:

From the balanced equation, two moles of acetylene gives four moles of carbon dioxide. Using dimensional analysis we could show the calculations for the formation of carbon dioxide by the combustion of 35.0 moles of acetylene.

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The next part is, how we choose 35.0 moles of acetylene and not 84.0 moles of oxygen.
From balanced equation, there is 2:5 mol ratio between acetylene and oxygen. Let's calculate the moles of oxygen required to react completely with 35.0 moles of acetylene.

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Calculations shows that 87.5 moles of oxygen are required to react completely with 35.0 moles of acetylene. Since only 84.0 moles of oxygen are available, the limiting reactant is oxygen, so 35.0 moles of acetylene will not react completely as it is excess reactant.
So, the theoretical yield should be calculated using 84.0 moles of oxygen as:

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Explanation:
Beryllium is a group 2 element and its atomic number is 4. Electronic configuration of beryllium is
.
Since, a beryllium contains two valence electrons so, in order to attain stability it will readily lose its 2 valence electrons.
Therefore, a beryllium atom upon losing two valence electrons will acquire a +2 charge.
Thus, we can conclude that the net ion charge of Beryllium is +2.
Answer:
1. Many different hypotheses will be tested.
Explanation:
Scientists test every hypothesis they make for their investigation, before moving onto bigger conclusions.
For the question given above, option 2 which is H-Cl pair of atoms has the most polar bond among the four of them.
The larger the value of the electronegativity, the greater the atom’s strength to attract a bonding pair of electrons. <span>Hydrogen has an electronegativity of 2.1, and chlorine has an electronegativity of 3.0. The electron pair that is bonding HCl together shifts toward the chlorine atom because it has a larger electronegativity value.</span>