Answer:
Option B. It is a basic solution.
Explanation:
To know which option is correct, let us calculate the pH of the solution.
First, we shall determine the pOH of the solution. This is illustrated below:
Concentration of Hydroxide ion, [OH¯] = 3.5×10¯⁶
pOH =.?
pOH = –Log [OH¯]
pOH = –Log 3.5×10¯⁶
pOH = 5.5
Finally, we shall determine the pH. This can be obtained as follow:
pOH = 5.5
pH =?
pH + pOH = 14
pH + 5.5 = 14
Collect like terms
pH = 14 – 5.5
pH = 8.5
The pH scale reads as follow:
0 to 6 => Acidic
7 => Neutral
8 to 14 => Basic
Comparing the pH of the solution (i.e 8.5) with the pH scale, we can conclude that the solution is basic because the pH of solution lies between 8 and 14.
Buffer is formed from weak acid and its salt with strong base (its conjugate base)
So the only one correct answer is :
0.2 M H₃PO₄ and 0.2 M NaH₂PO₄
While all other choices are incorrect
Answer:
0.2g of hydrogen is needed to produce 1.80g of water
Explanation:
No. of moles of water
From given values,
Weight of water 
Molecular weight of water 
No. of moles of water
From equation, it is clear that 2 moles of water can be formed by 2 moles of 
Hence, 0.1 mole of water can be formed from 0.1 mole of
Now,
No. of moles of 
Answer: B: Iron rusts when exposed to air.
Explanation:
The heat gained or lost by a substance undergoing a change in temperature is:
Q = mCpΔT
The heat lost by the iron is equal to that gained by water. The Cp for water is 4.186 Joules/gram
75 x 4.186 x (22.24 - 16.95) = -93.3 x Cp x (22.24 - 65.58)
Cp = 0.411 J/g
The heat capacity of iron is 0.45 J/g
%Error = [(0.45 - 0.41) / 0.41] x 100
%Error = 9.76%
