After eight long months, Microsoft has finally concluded its four and a half billion pound deal to acquire the mobile phone business of Finnish giant Nokia.

The deal sees Microsoft take possession of the Lumia smartphone brand, along with the company's lower-end Asha feature phone line and the intriguing Android-based Nokia X phones. It has also inherited 25,000 new employees.

While Microsoft is paying less than it when it bought Skype a few years ago, this is arguably a much bigger risk for the company.

As it looks to play catch up to Apple and Google in the smartphone market, getting this deal right, and making the most of what it has bought from Nokia will be critical for Microsoft's new CEO Satya Nadella.

In the coming weeks and months Microsoft will need to answer some tough questions to see if this deal will be a success or not:

1. Can it handle making 250 million phones a year?

Nokia may not be a major player in the smartphone market, but it is still the world's second biggest mobile phone manufacturer - shipping more than 250 million phones in 2013.

Microsoft already produces hardware like the Xbox consoles, Kinect sensors and Surface tablets but nothing on this scale, and it will need to make sure that the transition happens smoothly if it wants to maintain what is a lucrative business.

2. What is in a name?

Microsoft. Nokia. Lumia. Asha. Nokia X. Windows Phone. Android. Microsoft Mobile.

These are just some of the names involved in this deal and if Microsoft wants to really make its mark in the smartphone world it will need to make sure not to confuse potential customers with lots of names.

The Nokia name, which still carries a lot of weight, could disappear altogether, but whatever Microsoft decides to do, it needs to get its branding just right.

3. Software: Windows Phone, Android or Series 40?

Microsoft is a software company at heart but it has so far failed to make a serious impact on mobile. It's Windows Phone software has made slow but steady progress, but it now has to deal with two more operating systems.

Series 40 is Nokia's own software which runs on its Asha phones while a forked version of Android runs on the new Nokia Z smartphones.

Microsoft needs to streamline the number of operating systems it has to support and it is likely Series 40 could be cut loose.

4. How do you integrate two technology giants?

With the deal closing, Satya Nadella has 25,000 new employees to deal with.

While most of these won't be coming to Microsoft's Redmond campus, it will require a lot of thought and tact in order to integrate the two teams.

Doing so correctly will help get the most out of the Nokia deal, but failing to bring the former Nokia employees fully into the fold could create tension.

5. Is it worth the risk?

This is the million dollar question. Microsoft has been trying to break into the smartphone market for a number of years now, and while Windows Phone is improving, sales are still dwarved by the likes of Apple and Samsung.

This could be Microsoft's last throw of the dice to get mobile right and with Nokia's rich heritage of hardware innovation, combined with Microsoft's resources and software expertise, this could be a match made in technology heaven.