Of the reactions below, only is not spontaneous. A. Zn (s) + 2HI (aq) → ZnI2(aq) + H2 (g) B. 2Ag (s) + 2HNO3 (aq) → 2AgNO3 (aq) + H2 (g) C. Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2(g) D. 2Ni (s) + H2SO4 (aq) → Ni2SO4 (aq) + H2 (g) E. 2Al (s) + 6HBr (aq) → 2AlBr3 (aq) + 3H2 (g)

2Ag (s) + 2HNO3 (aq) → 2AgNO3 (aq) + H2(g)

Explanation:

Usually, metals displace hydrogen from dilute acids to form the corresponding salt of the metal and hydrogen. This in turn depends on the position of the metal in the electrochemical series. Metals below hydrogen in the electrochemical series cannot spontaneously displace it from dilute acids. Silver is below hydrogen in the electrochemical series, hence it cannot spontaneously displace hydrogen from dilute nitric acid as shown in the answer.

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.