Explain why phenol and aniline show negative deviation?Also why does Ethanol and Carbon disulphide show  positive deviation ?
Is there any method to know which mixture shows negative or positive deviation ?
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For positive deviation, A-B attractive force should be weaker than A-A and B-B attractive forces. 'A' and 'B' have different shape, size and character. p_A > p^o_AX_A; p_B >p^o_BX_B
.^.. p_A + p_B > p^o_AX_A +p^o_BX_B
That is ethanol and carbon disulphide shows positive deviation because ethanol-CS₂ shows weaker attractive forces. 
A-B attractive force should be greater than A-A and B-B attractive forces. 'A' and 'B' have different shape, size and character.
p_A < p^o_AX_A; p_{B <}p^o_BX_B
.^.. p_A + p_B < p^o_AX_A +p^o_BXB
​For phenol - aniline it shows negative deviation because the attraction  between phenol and aniline is more.