Answer:
The hydrogen ion concentration in a solution, [H+], in mol L-1, can be calculated if the pH of the solution is known.
pH is defined as the negative logarithm (to base 10) of the hydrogen ion concentration in mol L-1 pH = -log10[H+] ...
[H+] in mol L-1 can be calculated using the equation (formula): [H+] = 10-pH
For answering for the question, there exists four choices:
1) Na+ + e- -------------- Na
2) Na --------Na+ + e-
3) Cl2 + 2e- ------------ Cl-
4) 2Cl- ---------Cl2 + 2e-
reduction half-reaction general formula is
oxidant + e - or + -------- Product
so in our case the answer is
1) Na+ + e- -------------- Na (exactly balanced)
Biotic and abiotic factors are the environmental conditions that the organisms have to face to live in a specified environment.
-Abiotic factors-
Abiotic factors are the physical and chemical conditions of an environment. For example : heat, salinity, pressure, light, wind, pH ...
-Biotic factors-
Biotic factors are all the biological conditions of an environment for a specie/taxa. It can include prey and predator abundance, available food amount, available space, intra and interspecific competition...
The development of organims is under the control of abiotic factors. Some are adapted to heat, cold etc ... The abiotic factors will define which organisms are able or not to live in a specified place.
The living organisms will constitute the biotic factors, which define if and how can an organism live in a specified environment.
So, the abiotic factors are controling the biotic factors of an environment.
Hope it helps you !
Answer : The equilibrium will shift in the left direction.
Explanation :
Le-Chatelier's principle : This principle states that if any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.
The given reaction is:
As per question, when we are adding 
then the concentration of is increased on product side then the equilibrium will shift in the direction where decrease of concentration of takes place. Therefore, the equilibrium will shift in the left direction.
Thus, the equilibrium will shift in the left direction.
