Answer
Entropy is an extensive property of gas, but specific entropy is intensive property due to the involvement of mass. So the answer is yes for total entropy of the mixture. But the specific entropy of the mixture is not equal to the sum of specific entropy of individual gases.
Work Step by Step
Entropy is an extensive property of gas, but specific entropy is intensive property due to the involvement of mass. So the answer is yes for total entropy of the mixture. But the specific entropy of the mixture is not equal to the sum of specific entropy of individual gases.