It's Synthesis, single replacement is incorrect.
Explanation:
As per Brønsted-Lowry concept of acids and bases, chemical species which donate proton are called Brønsted-Lowry acids.
The chemical species which accept proton are called Brønsted-Lowry base.
(a) 
is Bronsted lowry acid and
is its conjugate base.
is Bronsted lowry base and
is its conjugate acid.
(b)

is Bronsted lowry base and HCN is its conjugate acid.
is Bronsted lowry acid and
is its conjugate base.
(c)

is Bronsted lowry acid and
is its conjugate base.
Cl^- is Bronsted lowry base and HCl is its conjugate acid.
(d)

is Bronsted lowry acid and
is its conjugate base.
OH^- is Bronsted lowry base and
is its conjugate acid.
(e)

is Bronsted lowry base and OH- is its conjugate acid.
is Bronsted lowry acid and OH- is its conjugate base.
Answer:
Mass = 36 g
Explanation:
Given data:
Mass of water formed = ?
Mass of hydrogen = 4.04 g
Mass of oxygen = 31.98 g
Solution:
Chemical equation:
2H₂ + O₂ → 2H₂O
Number of moles of hydrogen:
Number of moles = mass/molar mass
Number of moles = 4.04 g/ 2 g/mol
Number of moles = 2.02 mol
Number of moles of oxygen:
Number of moles = mass/molar mass
Number of moles = 31.98 g/ 32 g/mol
Number of moles = 1.0 mol
Now we will compare the moles of water with hydrogen and oxygen.
O₂ : H₂O
1 : 2
H₂ : H₂O
2 : 2
2.02 : 2.02
Number of moles of water formed by oxygen are less thus oxygen will limiting reactant.
Mass of water:
Mass = number of moles × molar mass
Mass = 2 mol × 18 g/mol
Mass = 36 g
I believe it's webbed feet
the temperature is decreased