Boiling point of water at 750 mm is` 99.63^@` C. How much of sucrose is to be added to 500 g of water so that it boils at `100^@` C.
`(K_b =0.052 )`

Explanation

`Delta T_b = 100-99.63 =0.37 K`
`K_b = 0.52 `
` M_B ` for `(C_(12) H_(22) O_(11)) =342 `
`W_A=500 g`
` W_B=(Delta T_b xxM_b xx W_A )/(1000 xx K_b)`
`=(0.37 xx342 xx 500 )/(1000 xx 0.52 )`
`=( 0.37 xx 171 )/( 0.52 )`
`= 121.7`g