Souce of income for house wife/home business

Prasanna (Engineer) (24 Points)

06 August 2016  

I am IT professional, my wife is house wife doing small business in house like tailoring, selling snacks, sarees etc..but not registered. 

I see for women <2.5lakhs income no tax. My wife wants to invest the money she earned in stock market. 

She has around 10 lakhs now, earned since 5 years (~ 2 lakhs per year, for which we never filed return)

So questions are below

1. I understand <2.5 lakhs income we dont need to file the return. If so, is it legal to invest her 10 lakhs
2. I am planning to invest this 10 lakhs in stock market around 1 year period. If the profit crosses above 2.5 lakhs am thinking of filing her tax. 
   Else will not do any. Is it fine?