It would never, ever happen. The increase in difficulty and the reduction in mining reward would mean that you would never, ever accumulate anywhere near 1 BTC with a mining speed that low. You would need to be more than a billion times faster.
Mining is perfectly competitive. Trying to mine with hardware like that is like trying to win a race to build a suspension bridge across a massive river using teaspoons and toothpicks when other people have flat beds full of steel and steamshovels.
Update: "kindly advise which one of theses two can i buy ..."
Why? Why would you want to enter a business you don't understand? I don't understand tailoring, so I'm not going to go out and buy the stuff to have a tailoring business. Having a bitcoin mining business requires you to get everything right because it is absurdly competitive. Were you to just get an S9i and hook it up in your home, you'd lose $45/month. And that assumes you don't need additional air conditioning to get rid of the 1.3Kw of heat it generates.
Update: I just read their FAQ -- they're not mining bitcoins at all, "In fact, CryptoTab software is mining Monero(XMR) and then converts them to Bitcoins in accordance with the current exchange rate, that is why your balance is displayed in BTC.".
I re-did the math using Monero, and I got a best case yield of minus $6/month. The exact amount depends on your electricity cost. That assumes you personally keep 100% of your mining reward, which I'm pretty sure you don't since you're in someone's downline and are paying for conversion to BTC and whatnot.
It seems like an obviously bad idea though. What's the benefit of combining the mining program with a browser? What conceivable advantage does that have over a separate mining program? And there are obvious downsides -- if I want to change mining programs, mining pools, or which coins I'm mining, I have to change browsers!