Is it permissible to engage in supplication (Du'a) during a silent prayer when the Imam prolongs the recitation before Rukoo', and is the supplication absolute or restricted?

It is preferable for the follower (ma'mum) to recite the Quran while the Imam is standing. If unable to do so, he should engage in supplication (du'a), and there is no specific supplication for this. If the follower finishes reciting Al-Fatiha and does not hear the Imam's recitation, or if the prayer is silent in the third or fourth rak'ah, it is sunnah for him to recite or supplicate. Recitation is more preferable because standing is its proper place. If he finishes the first tashahhud before his Imam, it is sunnah for him to supplicate and not to invoke blessings upon the family of the Prophet, as it is disliked in the first tashahhud.