Answer: -
0.2 Kg
Explanation: -
The equation used by Rhia for the carbon footprint measurement is
C = 0.2 B + 0.1 S
where S miles are by subway, B miles by bus and C is Kg of carbon dioxide.
From the equation we see the coefficient of B is 0.2.
Thus 0.2 Kg of carbon dioxide per mile the bus portion contributes to Rhia's carbon footprint.
RbOH + HBr = RbBr + H₂O
NaOH + HClO₄ = NaClO₄ + H₂O
rubidium bromide RbBr and sodium perchlorate NaClO₄ are formed by the strong basis and the strong acid
pH=7
Red blood cells are red because they contain Haemoglobin
Explanation :
According to the Bronsted Lowry concept, Bronsted Lowry-acid is a substance that donates one or more hydrogen ion in a reaction and Bronsted Lowry-base is a substance that accepts one or more hydrogen ion in a reaction.
Or we can say that, conjugate acid is proton donor and conjugate base is proton acceptor
The given equilibrium reaction is,

In this reaction,
and
are act as Bronsted Lowry base and acid respectively and
and
are act as Bronsted Lowry acid and base respectively.
The formula of conjugate of
is, 
The formula of conjugate of
is, 
The correct answer is B. The difference between the orbital period of planets Mercury and Earth is 0.76 years. The orbit of mercury is the most eccentric among the planets in the Solar system and the smallest planet. It has an orbital period of 88 Earth days.