Fluorine.
Because:- Atoms want to become stable, for an atom to become stable, they need 8 valence electrons. Since Fluorine has 7 valence electrons, it only needs one more electron to become stable and have an octet. An octet is when an atom/element has 8 valence electrons. Since Fluorine will need to gain an electron, it will have a negative charge, and become an anion.
That would be <span>Johannes Gutenberg a German inventor from the 1400's </span>
Correct answer is <span>X = ΔH
Reason:
1) The graph of enthalpy Vs reaction coordinate suggest the reaction is endothermic in nature. For endothermic reaction, energy if product is more than that of reactant. Hence, option 1 i.e. </span><span>X = -ΔH cannot be correct.
2) Since the reaction is endothermic in nature, </span>energy if product is more than that of reactant. Hence, option 2 i.e. X = ΔH is correct.
3) Activation energy is energy difference between Reactant (A) and transition state (B). However, as per option C, activation energy (A.E.) is energy difference between product (C) and transition state (B), which is incorrect.
Answer: 1.36 M
Explanation:
Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

where,
n = moles of solute
To calculate the moles, we use the equation:
moles of solute= 

The balanced reaction between barium hydroxide and perchloric acid:

To calculate the concentration of acid, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is 
We are given:

Putting values in above equation, we get:

Thus the concentration of the acid is 1.36 M
Answer : The volume of hydrogen gas at STP is 4550 L.
Explanation :
Combined gas law is the combination of Boyle's law, Charles's law and Gay-Lussac's law.
The combined gas equation is,

where,
= initial pressure of gas = 100.0 atm
= final pressure of gas at STP = 1 atm
= initial volume of gas = 50.0 L
= final volume of gas at STP = ?
= initial temperature of gas = 
= final temperature of gas at STP = 
Now put all the given values in the above equation, we get:


Therefore, the volume of hydrogen gas at STP is 4550 L.