!: (a) 20 cm: 80

10. Some mercury is poured into a capillary tube of

uniform bore and one end closed. When the tube

is held horizontally, mercury column has a length

of 4 cm and air enclosed in the closed end has a

length of 10 cm. If the tube is now held vertically,

with open end upwards, the length of the air

column will be (take atmospheric pressure at the

Tale place of experiment to be 760 mm)

(a) 10.5 cm . (6) 8.5 cm ",JI

(c) 9.0 cm mati (d) 9.5 cm 0

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