If the rate constant for some reaction is k = 3 × 10^-4 L mol^-1s^-1, then its order is:

Explanation:- 

R → P One mole of the reactant R produces one mole of the product P. If [R]₁ and [P]₁ are the concentrations of R and P respectively at time t₁ and [R]₂ and [P]₂ are their concentrations at time t₂ then,

Δt = t₂ – t₁, Δ[R] = [R]₂ – [R]₁, &

 Δ [P] = [P]₂ – [P]₁ 

• Consider a general reaction

a A + b B → c C + d D

Where a, b, c and d are the stoichiometric coefficients of reactants and products.

The rate expression for this reaction is

Rate ∝ [A]x [B]y , Rate = k [A]^x[B]^y 

⇒ dR/dt =  k [A]x[B]^y 

where k is a proportionality constant called rate constant.

Thus, rate law is the expression in which reaction rate is given in terms of the molar concentration of reactants with each term raised to some power, which may or may not be same as the stoichiometric coefficient of the reacting species in a balanced chemical equation. 

For a general reaction

→ aA + bB → cC + dD Rate = k [A]x [B]y

Where x + y = n = order of the reaction k = x Rate [A] [B]y n concentration 1 = × where [A] [B] time concentration

Taking SI units of concentration, mol L–1 and time, s, the units of k for different reaction order are listed.

Since the unit of Rate Constant is given as k = 3 × 10-4 L mol-1s-1 the unit matches with the second Order