A buffer system usually will need a weak acid, like H2CO3, which is carbonic acid, and a strong base, and the only compound that could figure a fairly strong base among the options given is Na2CO3. NH3 and NaHCO3 are weak bases and HF is a strong acid. Therefore the best answer will be letter A
MOVE ACROSS, OR PERPENDICULAR TO, THE DIRECTION THAT THE WAVE IS TRAVELING.
Answer:Since dinosaurs are thought to be over 65 million years old, the news is stunning - and more than some could tolerate. After the AOGS-AGU conference in Singapore, the abstract was removed from the conference website by two chairmen because they could not accept the findings. Unwilling to challenge the data openly, they erased the report from public view without a word to the authors. When the authors inquired, they received this letter:
Explanation:
i do not own my copyrights
Here are a few examples :)
iodine (I2)
naphthalene
aresenic (As)
ferrocene
water (H2O)
carbon dioxide (CO2)
Hope this helps :)
Answer:
Scandium is the most reactive
