Answer:
NaOH(aq)
Explanation:
NaOH(aq) is known to precipitate Mn^2+ ions according to the following reaction; Mn^2+(aq)+2OH^−(aq)↽−−⇀Mn(OH)2(s)
Hence, manganese(II) oxide reacts more readily with NaOH(aq) under ordinary conditions precipitating the metal hydroxide solid. This is one of the characteristic reactions of Mn^2+.
Answer:
the answer to your question is A
Answer : The value of new volume is, 50.0 mL
Explanation :
Boyle's Law : It is defined as the pressure of the gas is inversely proportional to the volume of the gas at constant temperature and number of moles.

or,

where,
= initial pressure at STP = 1 atm
= final pressure = 4.00 atm
= initial volume at STP = 200.0 mL
= final volume = ?
Now put all the given values in the above equation, we get:


Therefore, the value of new volume is, 50.0 mL