Answer : The correct expression will be:

Explanation :
The chemical reactions are :
(1)

(2)

The final chemical reaction is :

Now we have to calculate the value of
for the final reaction.
Now equation 1 is multiply by 2 and then add both the reaction we get the value of 'K'.
If the equation is multiplied by a factor of '2', the equilibrium constant will be the square of the equilibrium constant of initial reaction.
If the two equations are added then equilibrium constant will be multiplied.
Thus, the value of 'K' will be:

Answer:
Step-by-step explanation:
Alright, lets get started.
Suppose they take t minutes to meet each other.
Distance covered by first friend in t minutes, = 0.2 *t=0.2∗t
Distance covered by second friend in t minutes , =0.15 *t=0.15∗t
Total distance is given as 7, so
0.2 t + 0.15 t = 70.2t+0.15t=7
0.35 t = 70.35t=7
t = 20t=20
means after 20minutes they will meet.
SO. the average speed is 10m: Answer
Equation of reaction
Hcl+NaoH-->Nacl+H2O
1:1
Using the formula CaVa/CbVb=na/nb
Ca(Concentation of acid)= 0.100M
Cb(Concentration of base)=0.200M
Va=?
VB=50.00ml
na=1
nb=1
from the formula
Va= CbVbna/Canb
Va= 0.2*50*1/0.1*1
=10/0.1=100ml
Therefore volume of acid = 100ml
Answer is d. in hetrogeneous you can separate things from each other