On adding 1 g arsenic to 80 g benzene, the freezing point of benzene is lowered by 0.19° C. The formula of arsenic is (Kf=5,08 K kg mol -1).

Question

On adding 1 g arsenic to 80 g benzene, the freezing point of benzene is lowered by 0.19° C. The formula of arsenic is (Kf=5,08 K kg mol -1). (A) As (B) As 2 (C) As 3 (D) As 4

Tardigrade Admin · Accepted Answer

Δ Tf=(1000 Kf w/m W) Δ Tf=0.19° C ; Kf=5.08 K kg mol -1, w=1 g ; W=80 g m=(1000 Kf w/Δ Tf W)=(1000 × 5.08 × 1/0.19 × 80)=334.21 Atomic weight of As =74.92 Hence, number of atoms =(334.21/74.92) ≈ 4 Hence, the formula of arsenic is As 4.

Q. On adding $1 g$ arsenic to $80 g$ benzene, the freezing point of benzene is lowered by $0.1 9^{\circ} C$ . The formula of arsenic is $(K_{f} = 5, 08 K k g m o l^{- 1})$ .

$A s$

$A s_{2}$

$A s_{3}$

$A s_{4}$

Q. On adding 1g arsenic to 80g benzene, the freezing point of benzene is lowered by 0.19∘C. The formula of arsenic is (Kf​=5,08Kkgmol−1).

As

As2​

As3​

As4​

ΔTf​=mW1000Kf​w​ ΔTf​=0.19∘C;Kf​=5.08Kkgmol−1, w=1g;W=80g m=ΔTf​W1000Kf​w​=0.19×801000×5.08×1​=334.21 Atomic weight of As=74.92 Hence, number of atoms =74.92334.21​≈4 Hence, the formula of arsenic is As4​.

Q. On adding $1 g$ arsenic to $80 g$ benzene, the freezing point of benzene is lowered by $0.1 9^{\circ} C$ . The formula of arsenic is $(K_{f} = 5, 08 K k g m o l^{- 1})$ .

$A s$

$A s_{2}$

$A s_{3}$

$A s_{4}$