Buffer is composed of weak acid and its conjugate base or weak base and it is conjugate acid. so The correct answer is:
0.21 M hydrofluoric acid + 0.20 M potassium Fluoride
due to the first choice contain NaOH which is strong base not weak
second choice both salts no acid or base
Third choice contain HNO₃ which is considered as strong acid
Fourth choice contain ammonia but without its conjugate acid like (NH₄Cl for example) instead it has different salt
Fifth Choice contain HF which is weak acid and KF which is its conjugate base so this is the correct one
Answer:copper(II) sulfate, CuSO4> 2-pentanol, C5H11OH> methane, CH4>propane, C3H8.
Explanation:
Solubility depends on the ability of solute to interact effectively with a solvent. If water is the solvent, it interacts effectively with ionic substances. copper II sulphate is ionic and will be the most soluble in water, 2-pentanol, will interact effectively with water via hydrogen bonding. Between methane and propane, methane will interact better with water since it has a shorter alkyl chain than propane
c.
Explanation:
I mainly think its c. from my point of view because as yoy can see they showed observations and explained certain information and they didnt conclude it as it's TRUE they said theories meaning its and Idea and something that is not fully proven happend.