The effect of a catalyst on an equilibrium is to . Select one: a. increase the rate of the forward reaction only b. slow the reverse reaction only c. increase the equilibrium constant so that products are favored d. shift the equilibrium to the right e. increase the rate at which equilibrium is achieved without changing the composition of the equilibrium mixture

E

Explanation:

A catalyst is a substance which alters the rate of a chemical reaction. We check for the correctness of each of the options as follows:

A. Is wrong.

A catalyst can increase the rate of the forward and backward reaction

B. Is wrong

A catalyst does not slow the reverse reaction only. This particular case is the case of a negative catalyst

C is wrong

A catalyst has no effect on the equilibrium nor the equilibrium constant

D is wrong

Catalyst has no effect on equilibrium value

E is correct

Although Catalysts has no effect on equilibrium or its constant value, it can increase the the rate at which equilibrium is achieved by speeding up the reaction through bringing down the activation energy

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g