のに（目的）（Verb dictionary form + のに）— in order to / for the purpose of

[For the Purpose of / In Order To (Use)]

Connection: Verb dictionary form + のに

Expresses what something is used for or needed for. This のに is different from のに (contrast)! It indicates the purpose or use of an object or action.

Formation: Verb dictionary form + のに + (adjective/verb)

料理を作るのに便利です (convenient for cooking)
日本語を勉強するのに時間がかかる (it takes time to study Japanese)

Common Collocations:

~のに便利だ (convenient for ~)
~のに必要だ (necessary for ~)
~のに使う (use for ~)
~のに時間がかかる (takes time for ~)
~のにお金がかかる (costs money for ~)
~のに役に立つ (useful for ~)

Comparison:

のに (purpose) = "for the purpose of" - describes what something is FOR
ために (purpose) = "in order to" - describes the goal of an action
のに (contrast) = "even though" - expresses unexpected contrast

Examples: この道具は野菜を切るのに便利です。(This tool is convenient for cutting vegetables.) 家を買うのにたくさんのお金が必要です。(A lot of money is necessary to buy a house.) この辞書は日本語を勉強するのに役に立ちます。(This dictionary is useful for studying Japanese.)