The answer here is D - bases tend to feel slippery. This is because they tend to dissolve oils on your skin, reducing the friction between your fingers or hands when you rub them together.
Answer:

Explanation:
2C₄H₁₀ + 13O₂ ⟶ 8CO₂ + 10H₂O
n/mol: 4.3
13 mol of O₂ react with 2 mol of 2C₄H₁₀

Atomic mass / mass number / atomic weight
(all of which mean the same thing)
It is called a polyatomic ion.
Hope this helps!!!
do you mean polymers or organic compounds?