The final «هْ» in وَمَا أَدْرَاكَ مَا هِيَهْ is known as hāʾ as-sakt. It is not the pronominal hāʾ of «فَأُمُّهُ» and should not be assigned pronoun-hāʾ rules.
Preserve it when stopping on «هِيَهْ» and follow the transmitted reading; do not simply delete it.
Contrast:
مَا هِيَهْ — hāʾ of pause.
فَأُمُّهُ — pronoun hāʾ, capable of ṣilah in the right context.
رَاضِيَةٌ — tāʾ marbūṭah, sounded as a sākin hāʾ at pause.
Opening interactive controls...
Hāʾ of pause in hiyah
Al-Qāriʿah and Az-Zalzalah — Comparative Tajwīd Practice
The final «هْ» in وَمَا أَدْرَاكَ مَا هِيَهْ is known as hāʾ as-sakt. It is not the pronominal hāʾ of «فَأُمُّهُ» and should not be assigned pronoun-hāʾ rules.
Preserve it when stopping on «هِيَهْ» and follow the transmitted reading; do not simply delete it.
Contrast:
مَا هِيَهْ — hāʾ of pause.
فَأُمُّهُ — pronoun hāʾ, capable of ṣilah in the right context.
رَاضِيَةٌ — tāʾ marbūṭah, sounded as a sākin hāʾ at pause.