Ionic compounds are composed of an ion pair of opposite charge. Usually, the positive ion is a metal cation while the negative ion is a non metal anion. The two ions are held together by strong electrostatic interaction.
The cylinder with the greater precision is the 10 ml graduated cylinder.
Precision refers to the closeness of a measurement to the true value.
A 10 ml graduated cylinder will have greater precision because it has marks for every 2 ml, this will allow you to read your measurements to two significant figures.
The 50 ml graduated cylinder on the other hand has marks for every 1 ml, this graduation will only allow the user to record measurement up to one significant figure. And you know, the more the significant figures, the more precise the measurement are.
Answer : The partial pressure of 
is, 222.93 torr
Explanation :
Half-life = 2.81 hr = 168.6 min
First we have to calculate the rate constant, we use the formula :
Now we have to calculate the partial pressure of
The balanced chemical reaction is:
Initial pressure 760 0 0
At eqm. (760-2x) 4x x
Expression for rate law for first order kinetics is given by:
where,
k = rate constant
t = time passed by the sample = 215 min
a = initial pressure of 
= 760 torr
a - x = pressure of at equilibrium = (760-2x) torr
Now put all the given values in above equation, we get:
The partial pressure of = x = 222.93 torr
Since we assume both reactants have 1 equivalent of H+ and OH- ions, we can balance the moles out. The acid of concentration x will have (x M)(0.035 L) = 0.035x moles of acid. Meanwhile, for the base: (0.432 M)(0.0246 L) = 0.0106 moles of base. Since these must be equivalent:
0.035x = 0.0106x = 0.304 M
